John chapter1 verse 20-51

What was John the Baptist's response when asked by the priests and Levites from Jerusalem, "Who are you?" (John 1:19-21)

That he was not the Christ, nor Elijah, nor the Prophet.

How did John the Baptist identify himself when questioned by the Pharisees about his identity?

He said, "I am the voice of one crying out in the wilderness, 'Make straight the way of the Lord,' as the prophet Isaiah said." (John 1:23)

How did John the Baptist identify Jesus when he saw Him coming toward him?

John testified that He was the Lamb of God, who takes away the sin of the world, and that He was before him. (John 1:29-30)

What sign did John the Baptist see that confirmed Jesus's identity as the Son of God?

He saw the Spirit descend from heaven like a dove and remain on Him. He also witnessed the one on whom the Spirit descends is the one who baptizes with the Holy Spirit. (John 1:32-33)