If A is the brother of B; B is the sister of C; and C is the father of D
how is D related to A?
I. Brother
II. Sister
III. Nephew
IV. Cannot be determined

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