Logical Deduction Steps

We can solve this puzzle by combining the clues to build the family tree generation by generation.

1. 
   Establish the Generations:
   
   
   
   • Clue 6 ("A is the grandmother of F") tells us A is in Generation 1 and F is in Generation 3.
   
   
   • Clue 5 ("B is the brother of F") tells us B is also in Generation 3.
   
   
   • Clue 5 also says B is the "son of D," which places D in Generation 2 as the parent of B and F.
   
   
   
   


2. 
   Identify the Grandparents (Generation 1):
   
   
   
   • Clue 4 ("C, who likes Black colour, is the daughter-in-law of E") means E must be in Generation 1.
   
   
   • Since A is the grandmother, her husband must be the grandfather. Therefore, E is the grandfather, and the first married couple is {E, A}.
   
   
   
   


3. 
   Identify the Parents (Generation 2):
   
   
   
   • We know D is the parent of B and F, so D must be the child of the grandparents (E and A).
   
   
   • We also know C is the "daughter-in-law of E," meaning she is married to E's son. Since D is the son of E, C must be married to D.
   
   
   • Therefore, the second married couple is {D, C}.
   
   
   
   

Final Family Structure

Gen 1 (Grandparents): E (m) --- A (f)
               |
Gen 2 (Parents):      D (m) --- C (f)
               |
Gen 3 (Children):     B (m) and F
    

Conclusion: The two married couples in the family are E and A, and C and D.

Final Answer: The correct option is A. CD.