The correct answer "The majority of working teens"
Explanation:
In sentences, the subject includes the word or words that refer to the person or agent of the action. In the case of the verb to be, the subject is the agent described. Moreover, in sentences with a traditional structure, the subject is placed before the verb.
In the sentence "The majority of working teens are employed by restaurants, grocery stores, and department stores" the subject is "the majority of working teens" because of all of these words describe the agent of the action "are employed" or answer to the question "who are employed?". Moreover, you can identify this because it precedes the verb.
