If A $ B means A is brother of B; B * C means B is son of C; C @ D means C is wife of D; A # D means A is son of D.
How is C related to A?
I. Maternal grandmother
II. Maternal aunt
III. Aunt
IV. Mother
Question: 以下哪项是正确的？
Options:
A. 仅 III
B. 仅 II
C. II 或 I
D. 仅 I
E. IV 为真
Answer: E
True statement: IV