Encoded relations (+ = brother, × = son, % = “B is daughter of A”): Make M the <em>maternal</em> uncle of N. Meanings: A + B ⇒ A is brother of B; A × B ⇒ A is son of B; A % B ⇒ B is the daughter of A (i.e., A is parent of B and B is female). Which option ensures M is the mother’s brother (maternal uncle) of N? Choose the correct expression.

Decode

• M + O % N: M is brother of O; O % N means N is the daughter of O. If O is the mother of N (female parent), then M is the mother’s brother ⇒ maternal uncle.
• M + O × N: O is son of N — does not relate M to N’s mother.
• M % O × N + P: Contradictory genders (O is daughter of M, then O is son of N).
• “None of these”: unnecessary; the expression in (C) suffices under the standard assumption that O is N’s mother.

Note
Since A % B states only that “B is the daughter of A”, the parent A could be the mother or father. Here we assume O is the mother of N (a common convention in such questions) to satisfy “maternal” uncle.