Answer:
That something is a little bit like something else.
Step-by-step explanation:
A metaphor, as explained on wikipedia is: a figure of speech in which a word or phrase is applied to an object or action to which it is not literally applicable.
Meaning it can't be (A) and (B) and (C) don't make sense, because a metaphor is a comparison of two things in their similarity. Therefore, the answer is (D).