A is the brother of B. B is the sister of C. C is the father of D. Who is A to D?

1. A is B's brother and B is C's sister, so A and C are siblings (likely brothers). 2. C is the father of D, so D is C's child. 3. A is a sibling of D's father, hence A is D's uncle. 4. So option A is correct. _Source: SSC Stenographer Study Material, Chapter on Blood Relations (jkchrome.com, Mistral OCR'd PDF), section on uncle/aunt_