Final answer:
Jay Leno made the most jokes about Bill Clinton while hosting The Tonight Show. His tenure covered several presidencies, but Clinton was a frequent subject during the early years of Leno's stint as host.
Step-by-step explanation:
Jay Leno, the former host of The Tonight Show, was known for his nightly monologues, which often included jokes about current events and politicians. Among the options given: George W. Bush, Bill Clinton, Al Gore, and Barack Obama, Jay Leno made the most jokes about Bill Clinton. Leno's tenure at The Tonight Show spanned from 1992 until 2009, and again from 2010 to 2014, which covered the presidencies of Clinton and George W. Bush, with Clinton being the subject during Leno's early years on the show. However, it is essential to note that the number of jokes made about a public figure can fluctuate depending on current events and the prominence of the individual in the media at the time.