A is B's brother. C is A's mother. D is C's father. How is B related to D?

हल

1. 01

   A and B are siblings, so C, who is A's mother, is B's mother too.

2. 02

   D is C's father, so D is the grandfather of C's children.

3. 03

   B is therefore D's grandchild.

4. 04

   Nothing in the question tells us whether B is male or female, so the answer must not assume one.