Then the Pharisees who had been sent
The Pharisees who were sent stand in the same line of questioning.
The verse notes the broader delegation involved.
19And this was John’s testimony when the Jews of Jerusalem sent priests and Levites to ask him, “Who are you?” 20He did not refuse to confess, but openly declared, “I am not the Christ.” 21“Then who are you?” they inquired. “Are you Elijah?” 22So they said to him, “Who are you? We need an answer for those who sent us. What do you say about yourself?” 23John replied in the words of Isaiah the prophet: 24Then the Pharisees who had been sent 25asked him, “Why then do you baptize, if you are not the Christ, nor Elijah, nor the Prophet?” 26“I baptize with water,” John replied, “but among you stands One you do not know. 27He is the One who comes after me, the straps of whose sandals I am not worthy to untie.” 28All this happened at Bethany beyond the Jordan, where John was baptizing.