Final answer:
The Earth is destroyed in the novel titled Mostly Harmless from The Hitchhiker's Guide to the Galaxy series.
Step-by-step explanation:
The correct answer is C) Mostly Harmless. In the novel written by Douglas Adams, titled Mostly Harmless, the Earth is destroyed to make way for a new space express. This novel is part of the science fiction series called The Hitchhiker's Guide to the Galaxy, which is known for its humorous and satirical take on space travel and the universe.