A and B are children of D.
Who is father of A? Which statements are necessary?
1. C is brother of A and son of E
2. F is mother of B
I. Only 1
II. Only 2
III. Either 1 or 2
IV. 1 and 2 both

Question: 以下哪项是正确的？
Options:
A. 仅 II, B. III 或 I, C. 非 IV, D. I 或 III, E. IV 或 I
Answer: A
C
True statement: II