Read the given question and decide which of the following options is additionally required to answer the question.
A and B are children of C and D. A is a boy and has two sisters, while B has three brothers. How many children do C and D have?
1
E is the sister of A.
2
B is the sister of E, who is the daughter of C.
3
F and G are brothers of A.
4
C is the husband of D.