Question: How is R related to M ? Statements: M's brother is husband of P. P…

Concept: In a blood-relation data-sufficiency question, a statement (or a combination of statements) is sufficient only when it fixes the asked relation to ONE unambiguous term. If, even after using everything given, the relation could still be more than one term - most often because a linking person's sex is never stated - the data is treated as insufficient overall, even though some facts are known for certain.

Application:

1. Statement II alone: P is mother of R's sister. Since R's sister and R share the same mother, P is R's mother. This statement never mentions M's side of the family, so alone it cannot connect R to M.

2. Statement I alone: M's brother is husband of P, so P is married to one of M's siblings. This statement never mentions R at all, so alone it cannot connect R to M either.

3. Combining both: P is R's mother (from Statement II) and P is married to M's brother (from Statement I). So M's brother is R's father, which makes R the child of M's sibling - R is M's nephew or niece.

4. The two statements together fix WHICH sibling's child R is, but neither one states R's own sex, so together they still cannot fix whether R is specifically M's nephew or specifically M's niece.

Cross-check: Each statement alone plainly fails on its own - one never mentions R, the other never mentions M's side - which rules out Statement I alone, Statement II alone, and 'either one alone' being sufficient. Since even the combined facts leave R's sex undetermined, the two together still cannot produce one unambiguous relation term. So neither a single statement nor both together settle a definite relation between R and M.