If A $ B means A is brother of B; A # B means A is mother of B; A * B means A is daughter of B and A @ B means A is father of B.
Which shows P is grandfather of Q?
I. P @ Q $ R # S
II. P $ Q # R @ S
III. P # Q $ R @ S
IV. P @ Q # R $ S

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