What coloring book became a “New York Times” bestseller in 1962?

Trivia: What coloring book became a “New York Times” bestseller in 1962?

Ronald McDonald Fire Safety
JFK Coloring Book
Mickey Mouse (First Edition)
The Peanuts Coloring Book

Correct Answer: JFK Coloring Book

So why is this answer correct? : Featuring caricatures of President John F. Kennedy, the book stayed at No. 1 for 14 weeks.