Which sentence contains a verb in passive voice?

a. Where did you find my coat?

b. A commencement speech has already been written by the principal.

c. Times like these are precious.

d. Our neighbors invited us over for a barbecue.

Sentences can either used as active or passive voices. A sentence is active the subject pf the sentence is the one performing the action with the formula: subject + verb + receiver of the action. A sentence is passive when the subject is the one upon by the verb. The formula is subject + be + verb past participle + receiver of the action. In the sentences above, the answer is letter B: A commencement speech has already been written by the principal.