Anupam said to a lady, 'The only daughter of my wife's brother is sister-in-law of your sister's brother.'
How is lady's husband related to Anupam?
I. Maternal uncle
II. Uncle
III. Father
IV. Son-in-law

Question: 以下哪项是正确的？
Options:
A. 只有 IV, B. 仅 II, C. 仅 I, D. 以上各项均不成立
Answer: A
True statement: IV