Which sentence contains a subject complement?

Every weekday, traffic stops on all major freeways.

Our city's most pressing problem today is traffic.

It takes many commuters more than two hours to get home.

Idling cars pour exhaust fumes into the atmosphere.

B). Our city's most pressing problem today is traffic.

Explanation:

A subject complement is elucidated as the words or phrase (group of words) that immediately follows a linking verb. These words are usually an adjective, pronoun, or noun that function to either identify or describe the subject. While the linking verbs generally involve various forms of be (was/were, is, am, are, has been, etc.), seem, or become.

In the given question, the third sentence contains a subject complement i. e. 'traffic' (noun) as it follows the linking verb 'is' (form of 'be') and functions to identify the subject ('our city's most pressing problem') i. e. 'traffic.' Thus, option B is the correct answer.