Answer: C) unproven.
Step-by-step explanation: the denotation of a word is its literal meaning, the definition that we can find in a dictionary, a word can have several denotations (or definitions). In the given excerpt we can see the use of the word "theoretical" and then the affirmation that a theory is an idea, based on the excerpt and on the given information, we can say that the denotation of "theoretical" is something that is unproven.