Avanish is a friend of Harsh. Pointing to an old man. Avanish asked Harsh. "who is he?" Harsh replied, "his son is my son's paternal uncle." How is the old man related to Harsh?

Avanish is a friend of Harsh.

Avanish points to an old man and asks Harsh, "Who is he?"

Harsh replies, "His son is my son's paternal uncle."

The old man's son is Harsh's brother, this means that the old man is Harsh's father

So, the old man is related to Harsh as his father

Thus, correct answer is (a) Father