|A) If the data in statement I alone are sufficient to answer the question||B) If the data in statement II alone are sufficient answer the question|
|C) If the data either in I or II alone are sufficient to answer the question;||D) If the data in both the statements together are needed.|
From I, we conclude that F is the son of B.
From II, we conclude that B's wife is D's mother.
This means that D and F are the sons of B and D is the brother of F.
So, both I and II are required.