CHICAGO — It was saved as the final question of Duke big man Wendell Carter’s interview with the Knicks on Friday morning.

Because it is by far the only question that really matters. The Duke center, who played alongside likely top-three lottery pick Marvin Bagley III, was asked by general manager Scott Perry how he would fit with 7-foot-3 Kristaps Porzingis in the frontcourt.

“That was kind of how we ended our interview,’’ Carter said. “If I was to come to New York, how it would work playing alongside him, learning his style of play, fitting in with him in the low post?”

And?

“I think it would work very well,’’ Carter said. “We’re both interchangeable players who can play the 4, 5. He’s a great player. I’d learn a lot from him how to be a pro on and off the court. That’s something I’d love.”

That he adjusted so well with Bagley makes a Carter selection with the Knicks’ ninth pick not a stretch. He’s more a traditional big at 6-10 than a unicorn deluxe, averaging 13.5 points, 9.1 rebounds and 2.1 blocks in his one-and-done season.

Some mock drafts have linked Carter with the Knicks, who had a center glut this season that may no longer exist. Enes Kanter and Kyle O’Quinn may opt out, Joakim Noah may never again don a Knicks uniform and Willy Hernangomez is in Charlotte. Even rookie prospect Luke Kornet is unsigned for 2018-19.

Here’s the Carter Conundrum: Is it too much Porzingis duplication when the Knicks have an aching need for a small forward to replace Carmelo Anthony? Carter would bring more of a rebounding element to the front line whenever Porzingis returns from his ACL tear. And he has a face-up game, too.

“The NBA game is changing,’’ Carter said. “They want to get up and down the court more. No more two centers anymore. One has to be versatile and shoot from the outside.”

Carter admitted his offensive prowess, because of Bagley, became limited at Duke, which got bounced in the Elite Eight. Carter said he can do more.

“Bagley is a phenomenal player,’’ Carter said. “He came into college basketball, did what he was supposed to do. My role changed a bit but I’m a winner. I do whatever I had to do to win. That’s what I did last year.

“College basketball sometimes puts limitations on a lot of players. The NBA is more my realm on where I could show what I can do. On the offensive end, I didn’t get much of it at Duke, but I’m pretty versatile in terms of, I can bring the ball up the court sometimes and shoot from deep.”

Once called the draft’s sleeper, Carter said he has heard he can go anywhere from No. 3 to 17. In this new age, there still are doubts about Carter’s ability to guard in space, as coaches say. There’s no doubt, however, he’ll block shots with his 7-3 wingspan.

“Rebounding, defending, I’m very comparable in those departments,’’ Carter said. “But defending the perimeter is something I have to show people I’m able to do. I’m a competitor, especially on the defensive end. I have to show I can defend guards on pick and roll actions.”