If A + B means A is the brother of B; A x B means A is the son of B; and A % B means B is the daughter of A
then which of the following means M is the maternal uncle of N?
I. M + O x N
II. M % O x N + P
III. M + O % N
IV. None of these

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