Data Sufficiency — Relationship of M to N Question: How is M related to N? Statements: I. B is the daughter of M and the sister of Q. II. N is the son of K, who is B's grandfather.

Introduction / Context: This Data Sufficiency problem tests careful handling of family trees and multiple possibilities. The aim is to conclude the relation between M and N using the two statements, either separately or together.

Given Data / Assumptions:

• I: B is M's daughter and Q's sister.
• II: N is the son of K; K is B's grandfather (i.e., father of one of B's parents).
• Gender of M is unspecified; K could be on M's side or the spouse's side.

Concept / Approach: Build possible family trees consistent with both statements and check whether M's relation to N is uniquely determined. If more than one valid structure exists, the data is insufficient.

Step-by-Step Solution:

Verification / Alternative check: No additional constraint in either statement eliminates one of the above cases. Hence ambiguity remains.

Why Other Options Are Wrong:

• I alone or II alone: Neither links M and N at all.
• Either alone sufficient: False.
• Both sufficient: False because multiple valid relations remain.

Common Pitfalls: Assuming K must be on M's side without evidence; inferring genders/relations that are not given; overlooking in-law possibilities.

Final Answer: Neither I nor II is sufficient.