B and F are children of D.
A is grandmother of F. So, B and F represent third generation.
Now, C is the daughter-in-law of E. So, A and E form a couple and represent first generstion. A, being mother, is a female and so E is a male.
C is the daughter-in-law of E and so D is E's son. Thus, CD is the other couple and represents second generation.
C likes black, B likes pink. Green and yellow are the preferences of a couple. So, A likes yellow and E likes green. Now, F does not like red. So, F likes white and D likes red.
Now F likes white and so cannot be a lady. B is the son of D and hence a male.
Both F and B are males and both are children of D. So, F is the brother of B.