To answer this, we can return to the text itself to determine what is the best answer. We can also use historical data to help us understand what a pardoner was. Pardoners were people that sold pardons and indulgences, usually from the Pope. They were considered a part of the clergy, essentially, because of this service.
However, in "The Canterbury Tales," we know that Chaucer upended the societal norms of the people he portrayed. So, while in real life, the pardoner is a good man that sells things for the Pope, in his poem, he is not.
In the General Prologue, the Host determines that the pardoner is not to be trusted because on top of the "pardons" he carries, he also has other things that he has used to trick a parson out of two month's salary.
With this in mind, the best answer to this question is A. Keeping in mind the stereotypes Chaucer played with and the description he gives of the pardoner--mainly that he's shady--it is best to say he sells false relics and pardons to swindle people out of their money.