since a feedback in the circuit makes it sequential, it might be using dynamic gates. Not sure if they asked whether the circuit to be entirely combinational or can allow feedback. If feedback allowed then back to back inverters

There's quite an extended back and forth in actual interviews for questions like this, so nothing quite like real practice. The Prepfully Nvidia Hardware Engineer experts have actually worked in this role, so they're able to do an honest-to-God accurate mock, which really puts you through the paces. prepfully.com/practice-interviews