A is father of B. C is wife of D. E is son of C. B is sister of E.
How is D related to A?
I. Son
II. Brother
III. Father
IV. Son-in-law
Question: 以下哪项是正确的？
Options:
A. 仅 IV
B. 仅 II
C. 仅 III
D. 仅 I
Answer: A
True statement: IV