Which angel was told to explain the vision of the ram and the goat to Daniel?

Answer: Gabriel

A man's voice called out, "Gabriel, explain the vision to this man," and when Gabriel came near, Daniel fell facedown in terror.

“And I heard the voice of a man calling from between the banks of the Ulai: “Gabriel, explain the vision to this man.” As he came near to where I stood, I was terrified and fell facedown. “Son of man,” he said to me, “understand that the vision concerns the time of the end.””— Daniel 8:16-17 (BSB)