Let's analyze the relationships step-by-step:
- a is the brother of b
- a and b are siblings; a is male.
- b is the sister of c
- b and c are siblings; b is female.
- c is the father of d
- c is male and the parent of d.
From the above:
- a, b, and c are siblings (a and b are brother and sister, b and c are sister and brother).
- c is the father of d.
Therefore:
- a is the uncle of d (since a is the brother of d's father).
Conclusion:
d is the nephew or niece of a.
- If d is male, d is a nephew.
- If d is female, d is a niece.
