A is father of B and C is sister of A. D is grandson of C. How is D related to B?

Tracing the family tree step by step: 1. A is the father of B, and C is the sister of A. Thus, C is the paternal aunt of B. 2. The child of C is B's cousin (belonging to the same generation as B). 3. D is the grandson of C, which means D is the son of C's child (that is, the son of B's cousin, placing D one generation below B). Because D is a male one generation below B (the son of B's cousin), D is the 'Nephew' of B . Uncle is one generation above B, Brother is in the same generation as B, and Grandson is two generations below B.