According to the preface, what is the main topic of The Pluto Files?

a. The story of how Dr. Tyson became an astrophysicist

b. The history of the American Museum of Natural History

c. A record of Pluto's rise and fall from planethood

d. How Dr. Tyson became interested in Pluto

The correct answer is C, the main topic of The Pluto Files is 'a record of Pluto's rise and fall from planethood'.

Pluto Files with its full name The Pluto Files: The Rise and Fall of America's Favorite Planet is a book written by American astrophysicist Neil De Grasse Tyson. From its full name, the answer is obvious, however in the opening paragraph of the preface author says that:

"Gathered here in one place is a record of Pluto’s rise and fall from planethood, given by way of media accounts, public forums, cartoons, and letters I received from disgruntled school children, their teachers, strongly opinionated adults, and colleagues."