Blood relations – counting definite sons: M is the brother of K. T is the sister of K. R is the father of M. J is the wife of R. How many sons does J have?

Introduction / Context:
The task is to infer the number of sons of J using given sibling and parent relationships, without over-assuming unspecified genders.

Given Data / Assumptions:

• M is brother of K ⇒ M is male; K's gender unknown.
• T is sister of K ⇒ T is female; K's gender still unknown.
• R is father of M; J is wife of R ⇒ J is mother of M (and likely of K, T).

Concept / Approach:
We know one definite son of J: M. Whether K is a son or daughter is not stated. T is a daughter. Therefore, total sons of J could be 1 (if K is female) or 2 (if K is male). The data does not pin down K's gender.

Step-by-Step Solution:

Verification / Alternative check:
Create two consistent family snapshots: (i) K male ⇒ sons = 2; (ii) K female ⇒ sons = 1. Both satisfy all statements, confirming ambiguity.

Why Other Options Are Wrong:
Any fixed number (1, 2, 3, 4) asserts information not supported by the statements.

Common Pitfalls:
Assuming K is male because M is a brother; "brother of K" doesn't force K's gender.

Final Answer:
Data inadequate