Find the odd one out?

Three of the four pairs of words given below are alike in a certain way and thus form a group. Which is the one that does not belong to the group?

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.

Find the odd one out from the following:

In the questions given below, select the one which is different from the other three responses.

In the fictional country of Petreversia, which of the following provinces is the odd one out?