CNN arranged Monday's Democratic presidential "town hall" forum so the last question of the night to Hillary Clinton was who her favorite president was, leading some viewers to question the event's authenticity.

As the two-hour event in Des Moines, Iowa, came to a close, with Clinton as the last of three candidates to take the stage, the final question came from a young student identified as Brett Rosengren.

"I can see why they gave you this question," Rosengren said, implying that his question was saved for Clinton's appearance. "I just wanted to know which of our previous presidents has inspired you most and why."

Clinton answered that it was Abraham Lincoln, but some viewers on social media said Rosengren's question seemed to reveal something about the event's format.

"Was he handed this question? Is CNN scripting this?" asked Ric Grenell, a conservative political commentator for Fox News.

A fan account for Clinton's Democratic rival, Bernie Sanders said, "They literally asked Hillary Clinton who was favorite president was. CNN really felt that was a reasonable question?"

A CNN source told the Washington Examiner media desk that producers picked the question especially for Clinton because of her former president husband. The source said producers also felt the question was best suited to be the last one asked. The source denied, however, that CNN wrote the question or "planted" it.

The event was billed as a "a chance for the people who will decide [the election] to ask the questions themselves." Cuomo said at the top of the program that the questions were cleared by CNN "to make sure they cover a variety of important issues."

A spokesperson for CNN declined to comment for this article.