Looking at a portrait of a man, Harsh said, "His mother is the wife of my father's son. Brothers and sisters I have none." At whose portrait was Harsh looking?

Explanation:-

Since Harsh has no brother and sister, so he is his father's only son.
So, wife of Harsh's father's son---Harsh's wife. Thus, Harsh's wife is the man's mother or the man is Harsh's son.