Selecting Words - Verbal and Reasoning

Q1:

He is a very careful person, he never takes side but remains ......

A impartial

B unbiased

C neutral

D prejudiced

ANS:A - impartial

Prejudiced means To cause(someone) to judge prematurely and irrationally.
but here he is very careful person therefore prejudiced is wrong

Also Unbiased means showing no prejudice for or against something; (BUT HERE NO SCENARIO IS MENTIONED AGAINST OR FOR WHICH HE WILL ACT).

THEREFORE CORRECT IS IMPARTIAL.