First, I don't envy you the comments of people who "suggest" which other answers should be included in your quiz. That said...
The question on the U.S. president should be reworded or LBJ should be accepted. Yes, JFK preceded LBJ, but LBJ was older. So he too could be considered the "1st U.S. President born in the 20th century" depending on how that question is interpreted.
This is a great general knowledge quiz, can’t believe I’m the first to nominate it. Maybe lose the Bill Cosby question? Clinton’s shenanigans were way funnier…
The question on the U.S. president should be reworded or LBJ should be accepted. Yes, JFK preceded LBJ, but LBJ was older. So he too could be considered the "1st U.S. President born in the 20th century" depending on how that question is interpreted.