Which of the following sentences is an example of a monologue? A) "I closed the door for you," said Mary.

B) "That's unusual," I thought, "I was certain I left the door open."

C) Sarah commented, "You often forget what you are doing."

B

Explanation:

First, let's define a monologue.

A monologue is when one sole character talks (to themselves), used most often to "express their thoughts out loud" (according to Wikipedia)

In this problem, there is only one answer choice which uses the words "I" and "thought", which signify somebody thinking to themselves.

Therefore, B is the answer choice.

Hope this helps! :)

the eye wink at the hand; yet let that be / which the eye fears, when it is done, to see.