“They were utterly amazed
καὶ ἐξεθαύμαζον ἐπ’ αὐτῷ.
There is something similar in Matthew, chapter 22:22, and in Luke, chapter 20:26, where the Pharisees and Herodians were amazed, but there was no mention of them leaving as in Matthew, or being silent as in Luke. Mark said that when these disciples of the Pharisees and Herodians heard this response, they were amazed or marveled at Jesus (καὶ ἐξεθαύμαζον ἐπ’ αὐτῷ). They had failed to trip up Jesus, as was their plan.