Pointing to Dilip in a photograph a woman said, "He is the only son of my mother's father". How is the woman related to Dilip?

Niece Sister Daughter Granddaughter

Niece

Explanation: Note: ↑ or ↓ ⇒ Upward or downward line shown "generation gap" .    =    ⇒ Double lines shown "relation b/w Husband & Wife"    —   ⇒ single line shown "relation between them other than Husband & Wife".