Mark Zuckerberg was repeatedly stumped during Congresswoman Alexandria Ocasio-Cortez’s questioning of him at the House financial services committee on Wednesday afternoon, appearing unable to answer even basic questions about one of his company's largest scandals.

The 35-year-old Facebook CEO appeared before the committee as his company seeks approval to launch its proprietary cryptocurrency project, Libra.

Ms Ocasio-Cortez, the 30-year-old New York Democrat elected in 2018 as the youngest woman to serve in the US House of Representatives, grilled Mr Zuckerberg about his platform’s controversial fact-checking policies after Facebook announced it would effectively allow politicians to lie in the platform's advertisements.

The congresswoman also questioned Mr Zuckerberg about Cambridge Analytica, a British consulting firm that harvested millions of Facebook profiles without consent for political advertising purposes during the 2016 presidential election.

The CEO stammered through his responses, at times correcting his own answers later on in the questioning and occasionally stating he didn’t know or simply could not remember when he became aware of the firm and its practices.

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Here are six of the questions that most confounded the Facebook CEO:

1. When did Facebook’s leadership become aware of Cambridge Analytica?

AOC: What year and month did you personally first become aware of Cambridge Analytica?

MZ: I'm not sure of the exact time. But it was probably around the time when it became public. I think it was around March of 2018. I could be wrong.

AOC: When did Facebook's COO Sheryl Sandberg become aware of Cambridge Analytica?

MZ: I don't know.

AOC: Did anyone on your leadership team know about Cambridge Analytica prior to the initial report by The Guardian on December 11, 2015?

MZ: Congresswoman, I believe so. Some folks were tracking it internally. As you're asking this, I do think I was aware of Cambridge Analytica as an entity earlier, I just don't know if I was tracking it.

2. When was the Cambridge Analytica hack discussed with Facebook’s first major investor, Peter Thiel?

AOC: When was the issue discussed with your board member Peter Thiel?

MZ: Congresswoman, I don't know that.

AOC: This was the largest data scandal with respect to your company that had catastrophic impacts on the 2016 election. You don't know?

MZ: I'm sure we discussed it after we were aware of what happened.

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3. Can a politician lie about Election Day on a Facebook ad?

AOC: You announced recently that the official policy of Facebook now allows politicians to pay to spread disinformation. In 2020 election and in the future. So I just want to know how far I can push this in the next year. Under your policy using census data as well, could I pay to target black predominantly zip codes and advertise them the incorrect election date?

MZ: No, congresswoman, you couldn't. We have even for these policies around the news worthiness of content that politicians say and the general principle that I believe —

AOC: But you said you're not going to fact check my ads.

MZ: If anyone including a politician is saying things that can cause violence or could risk eminent physical harm or voter or census suppression, we roll out the census suppression policy. We will take that content down.

AOC: So you will - there is some threshold you will fact-check political advertisements. Is that what you're telling me?

MZ: Congresswoman, yes, for specific things like that whether where there's imminent risk of harm.

4. Just how far can a politician lie in a Facebook ad?

AOC: Could I run ads targeting republicans in primaries saying they voted for the Green New Deal?

MZ: Can you repeat that?

AOC: Would I be able to run advertisements on Facebook targeting Republicans in primaries saying they voted for the Green New Deal? If you're not fact-checking political advertisements I'm trying to understand the bounds here of what's fair game.

MZ:: I don't know the answer to that off the top of my head.

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5. Does Facebook see a problem with its lack of fact-checking capabilities?

AOC: Do you see a potential problem here with a complete lack of fact-checking on political advertisements?

MZ: Congresswoman, I think lying is bad. I think if you were to run an ad that had a lie that would be bad. That's different from it being — in our position, the right thing to prevent your constituents or people in an election from seeing that you had lied.

AOC: So you won't take down lies or you will take down lies? It's a pretty simple yes or no.

MZ: Congresswoman, in most cases, in a democracy I believe that people should be able to see for themselves what politicians that they may or may not vote for for themselves.

AOC: You won't take them down? You may flag that it's wrong, but you won't take it down.

MZ: Congresswoman, it depends on the context that it shows up, organic post, ads.

6. Why is Facebook allowing Daily Caller to fact-check articles on its platform?

AOC: Can you explain why you named the Daily Caller, a well-documented publication with ties to white supremacists as an official fact checker for Facebook?

MZ: Sure. We don't appoint the independent fact checkers. They go through an independent organisation called the Independent Fact Checking Network that has a rigorous standard for who they allow to use as a fact checker.

AOC: So you would say that white supremacist-tied publications meet a rigorous standard for fact checking?