What is the role of a subject in a sentence?

The role of a subject in a sentence is to identify who or what is performing the action of the verb. This is clearly represented by the correct choice. The subject can be a noun or a pronoun, and it establishes the focus of the sentence. For instance, in the sentence "The dog barks," "the dog" is the subject because it is the entity that is carrying out the action of barking. Recognizing the subject is crucial to understanding sentence structure, as it provides the main actor in the action described by the verb.