Everyone could see that it was a prejudiced decision.

Answer: Option A

Prejudiced : having or showing a dislike or distrust that is derived from prejudice; bigoted.
Unbiased : showing no prejudice for or against something; impartial.
Candid : truthful and straightforward; frank.
Helpful : giving or ready to give help.
Logical : of or according to the rules of logic or formal argument.

Antonym of Prejudiced is Unbiased