I believe that the answer is c. but it could be d.
Answer:
I can't see the whole question
Explanation:
If you give me 5 stars and thanks I will give correct answer.
Answer:
1.) The sentence should say, "Diego Alvarado, who was my college classmate, writes excellent book reviews and speeches."
Explanation:
A comma creates a pause in a sentence as the reader reads the text. Since this person is providing extra info about Diego, they should put a comma to separate it from the overall message.