A is B’s father. C is B’s sister. D is A’s wife. How is D related to C?

Correct — A.
Rule: siblings share their parents, and a father's wife is read as the children's mother.

A is B's father.
C is B's sister, so C is also A's child.
D is A's wife, so D is the mother of A's children.

D is C's mother → option (a).

Why the others are wrong

• (b)
  Grandmother — Grandmother is two generations up. D is the wife of C's father, one generation above C, not the mother of one of C's parents.
• (c)
  Aunt — Aunt is a parent's sister, or an uncle's wife. D is married to C's own father, A, so she is C's mother, not an aunt.
• (d)
  Cousin — Cousin is the child of a parent's brother or sister, in C's own generation. D is A's wife, one generation above C.

Blood-relation items are solved by drawing the family one statement at a time: a vertical line from parent to child, a horizontal link for a married couple.

A is a father with two children, B and C, since C is B's sister. D is joined to A as his wife. A couple's children are read as the children of both, so D is C's mother.

Key facts

• A brother and sister share their parents, so B's father A is also C's father.
• The wife of a person's father is read as that person's mother.
• An aunt is a parent's sister, and a cousin is the child of a parent's brother or sister.

Common traps

• Linking D to B only and forgetting that C, as B's sister, is a child of the same father
• Choosing aunt because D is introduced through A rather than through C

No directly related past PYQ was found.