Only One of the Statements Below Uses the Term Theory

Multiple Choice

Only one of the statements below uses the term theory in its correct, scientific sense. Which one?

A) Evolution is only a theory, so there's no reason to think it really happened.
B) I wrote a theory that is 152 pages long.
C) Einstein's theory of relativity has been tested and verified thousands of times.
D) I have a new theory about the cause of earthquakes, and I plan to start testing it soon.