What is the use and meaning of the underlined portion of the sentence below?

The wooden splinter felt as sharp as a needle when it pierced my skin.

A.
It is a hyperbole to illustrate how the wooden splinter felt to the narrator.

B.
It is a metaphor used to compare the wooden splinter to a sharp needle.

C.
It is a simile used to compare the wooden splinter to a sharp needle.

D.
It is imagery to illustrate how the wooden splinter felt to the narrator.

B.

It is a metaphor used to compare the wooden splinter to a sharp needle.

In this sentence, the writer is indirectly comparing the sharpness of the wooden splinter to that of a needle by using "as sharp as a needle."