Answer:
D. It informs the reader about Pluto's planetary status
Explanation:
There are four main types of writing: descriptive, persuasive, narrative and expository.
The main purpose of expository (sometimes named informative) writing is, as the name might suggest, to explain, define something or inform the readers on a certain topic providing an explanation.
This particular sentence informs us about "Pluto's rise and fall from planethood" which means that it is no longer considered a planet.
In that way, it explains us Pluto's planetary status, which makes this an example of expository writing.
