what is the subject of the sent?

after her dog ran away from home, my friend began calling area pet shelters.
A.my
B.home
C.friend
D.dog
i think it is D

"Dog" is the subject of the subordinate clause, but not the subject of the main clause of the sentence.

So it is C?

Yes, C (friend) is the subject of the main clause.

what would be the best punctuation for this sentence Professor Jones is running late she had to change a flat tire.

Professor Jones is running late she had to change a flat tire

To determine the subject of a sentence, you need to identify the noun or pronoun that performs the action or is described in the sentence. In this case, the subject is "my friend." The sentence is about what your friend did, which is calling area pet shelters. Therefore, the correct answer is C. "friend."