Assuming you are asking for an explanation why, the correct answer is correct because it uses 'whom' in the context of 'to whom'. Whom should be used in place of whom if you can say 'to who' or 'for who', or if you can replace it with a him/her. The correct sentence can also be rearranged to "The award was given to ____"; here, you can use him, her, or 'whom?'.
