Question

A family has seven members, A, B, C, D, E, F and G. Among them there are three married couples. B, an engineer, is the father of E, who is a student. F, a contractor, is the grandfather of E. C is the daughter-in-law of D, who is a professor. G, a doctor, is the uncle of the student E. Among the seven members there is one journalist, one housewife and one student. C is the sister-in-law of B. The student, E, is single.

Which are the three married couples?

• A. (A, B), (C, G), (D, F)
• B. (A, F), (B, C), (D, G)
• C. (A, G), (B, C), (D, F)
• D. (A, B), (C, F), (D, G)

Hint:

Fix the grandparent couple (D, F) first, then split their two sons as B (married to A) and G (married to C, since C is B's sister-in-law).

Answer 1

The Correct Option is A

Step 1: Check each option against the "grandfather" clue.
F must be married into the oldest generation, since he is E's grandfather. In option (b), F is paired with A, which would make A the grandmother, but then D would need to be a fourth generation figure with no fixed spot, since D is separately tied to C as a mother/father-in-law figure of the same generation as F. This creates two competing "grandparent" pairs, which the family of 7 cannot hold, so option (b) fails.

Step 2: Check the "daughter-in-law of D" clue.
Option (d) pairs C with F, not with a son of D, so C would not be D's daughter-in-law at all under that pairing, contradicting the given clue directly. Option (d) is ruled out.

Step 3: Check the "sister-in-law of B" clue.
Option (c) pairs B directly with C, making C his wife. But the clue calls C the sister-in-law of B, and a wife is never her own husband's sister-in-law, so option (c) contradicts the clue and fails.

Step 4: Confirm the surviving option.
Option (a), (A, B), (C, G), (D, F), keeps F and D together as the grandparent couple, keeps C married to G so that C is D's daughter-in-law through G and B's sister-in-law through G being B's brother, and keeps A as B's wife and E's mother. Every clue is satisfied at once, and no other option manages this.

Final Answer:
The three married couples are (A, B), (C, G) and (D, F). \[ \boxed{(A,B),\ (C,G),\ (D,F)} \]