This question is incomplete because the question itself is missing; here is the missing section:
What is "Carl Sandburg" in the above sentence?
The correct answer is A. Simple subject
Step-by-step explanation:
In sentences, the simple subject includes the main words that indicate who is performing the action. This contrasts with the complete subject that indicates further details about the subject or agent of the action. In the case of the sentence presented, the section "Carl Sandburg" is the simple subject because these two words are the main words that indicate who was born. On the other hand, details such as "the now famous..." are part of the complete subject. Moreover, the sections that indicate the action and other details are the predicate.