Pointing to a person, a man said to a woman, 'His mother is the only daughter of your father". How was the woman related to the person?

Explanation Option (b) is correct. Such questions can be easily solved by adopting a method of ?backtracking?, i.e., starting from the last information and proceed backward. For example, if it is given that he is the son of the mother of my grandfather?s daughter. Only daughter of woman?s father = woman itself. The person?s mother is the woman itself. Hence, the woman is the person?s mother So, answer is (B).