Among the four women, who is the tallest? Statements: I. B is taller than C,…

Concept: A data-sufficiency statement (or combination of statements) is sufficient only when it pins down a single, unambiguous answer to the SPECIFIC question asked -- it need not fix every relationship in the scenario, only the one fact or position being asked about. Here the question asks only who is tallest, so a statement is sufficient the moment it identifies that one woman without ambiguity, even if other relative positions stay unknown.

1. Statement I gives B > C and A > B, so it fixes the relative order of three women: A > B > C. It says nothing about the fourth woman, D, so D could be taller than A or shorter than C -- the tallest cannot be fixed from Statement I alone.

2. Statement II gives C > D only. It places no information about A or B, so the tallest among all four cannot be identified from Statement II alone.

3. Combine both: Statement I gives A > B > C and Statement II gives C > D. Since C is common to both, the two partial orders chain together into one complete order: A > B > C > D.

4. In this complete order, A stands above every other woman, so A is the tallest with no ambiguity -- both statements together are sufficient, but neither alone is sufficient.

Cross-check: try to break the combined order -- is there any arrangement consistent with both statements where someone other than A is tallest? Any such arrangement would need to place another woman above A, but the chain A > B > C > D directly rules that out, confirming the combined statements are sufficient.