Pointing to a woman, Venus said, "She is the daughter of the only child of my grandmother". How is the woman related to Venus?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Sister
The statement is read from the end, one relation at a time:
“the only child of my grandmother” — Venus’s parent is a child of the grandmother; since she has only one child, that child must be Venus’s own father or mother.
“the daughter of” that parent — a daughter of Venus’s parent is Venus or Venus’s sister. Venus is pointing at another person, so the woman is Venus’s sister.

The word “only” settles it: the grandmother has no other child, so there is no uncle or aunt whose daughter could be Venus’s cousin.