Consider the following pair of words which are related to each other:
I: TEACHER – STUDENT
II: COACH – PLAYER
III: MENTOR – MENTEE
IV: FATHER – SON
Identify the odd pair.

Logic: In pairs I, II, and III, the relationship is professional/educational guidance.
(I) TEACHER : STUDENT → Pair of teaching/mentoring relationship.

(II) COACH : PLAYER → Pair of teaching/mentoring relationship.

(III) MENTOR : MENTEE → Pair of teaching/mentoring relationship.

(IV) FATHER : SON → Pair of biological relationship. 

In pair IV, the relationship is biological/familial, not professional.

Thus, the correct option is (b).