With Trump University at the center of an ongoing scandal, Republican presidential candidate Donald Trump is finding himself on the defensive about the business venture.

"We have a 98 percent approval rating, we have an A from the Better Business Bureau (BBB) and people like it," Trump said at the GOP primary debate Thursday.

Rival Marco Rubio said Trump's claim was "false. That's a D-. Go on my website."

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Fox News host and debate moderator Megyn Kelly intervened, confirming Rubio was right, and "the rating from the BBB was a D- and it was a result of a number of complaints they received."

Trump shot back that the rating was "elevated to an A."

Rubio also pointed out that Trump had claimed that he handpicked instructors at the school. Factcheck.org, however, pointed out that in a deposition, a top school executive admitted that no, "none of the instructors" had been chosen by Trump.

In reality, the school, which is currently facing a class action lawsuit of 5,000 people who say they were scammed, has received several ratings from the consumer interests organization.

According to a PolitiFact investigation, the BBB had given Trump's school ratings ranging from an A+ to D-. But the most recent rating recorded, in 2010, was a "D-" rating.