Amber reads these sentences aloud

Lia and Juliana left flyers for their new dog-walking, business at the homes of their closest neighbors. Lia said, "I really want to go to the state fair this summer! Do you think we can save enough money from our dog- walking business?"

Which punctuation mark tells Amber to raise her voice at the end?
a. the period
b. the comma
c. the exclamation mark
d. the question mark