A * B means A is sister of B; A $ B means B is mother of A; A + B means A is brother of B; A = B means B is father of A.
Which means M is maternal uncle of N?
I. M = P + Q * N
II. N + P = Q * M
III. N * P $ Q * M
IV. None

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