Actually when the disciples said "Some say..." they are in fact answering the question they were asked, not just relying on what others said. Then Jesus point blank asks "Who do ?YOU say I am?" and the only response the Gospel writer records is Peter's, we don't know how/if the others would have answered the second question. That is exactly what the text you posted says.
You are right here
---my bad ------they were answering His question -------Thanks for the correction -----verse 13 --and 14 go together--
“Who do people say the Son of Man is?”
Peter's Declaration about Jesus(H)
13 Jesus went to the territory near the town of Caesarea Philippi, where he asked his disciples,
“Who do people say the Son of Man is?”
14 (I)“Some say John the Baptist,” they answered. “Others say Elijah, while others say Jeremiah or some other prophet.”
15 “What about you?” he asked them. “Who do you say I am?”
16 (
J)Simon Peter answered, “You are the Messiah, the Son of the living God.”
17 “Good for you, Simon son of John!” answered Jesus. “For this truth did not come to you from any human being, but it was given to you directly by my Father in heaven.18 And so I tell you, Peter: you are a rock, and on this rock foundation I will build my church, and not even death will ever be able to overcome it.