Pointing to a photograph, Vipul said, "She is the daughter of my grandfather's only son." How is Vipul related to the girl in the photograph ?

A. Father
B. Brother
C. Cousin
D. Uncle
E. Grandson
Answer: B . Brother

Justification: My grandfather's only son -- My father.
So, the girl is the daughter of Vipul's father i.e., Vipul is the girl`s brother.