The correct answer is A.
A prejudice is an emotional and generally negative feeling developed towards a person or a human group, based on a certain piece of information known about this person/group, which is considered wrong and from which other preconceived ideas are assumed.
In the example provided above, the person is avoided because the interlocutor doesn't like the only feature that he knows about that person, the way he talks, and concludes that this person is underisable from his viewpoint, without gathering any further information.