Andre first became suspicious of his roommate's honesty while trying to account for his own missing wallet. although andre later recalled that he had left his wallet in the glove compartment of his own car, his newly formed doubt about his roommate's honesty remained as strong as ever. andre's irrational suspicion of his roommate best illustrates:

The correct answer is the belief perseverance phenomenon.
As the name itself says, this phenomenon has to do with a particular belief sticking with you even though it was originally based on faulty assumptions. So, Andre thought that his missing wallet was stolen by his roommate - and even though he later found out that wasn't the case, still the distrust of his roommate remained, even though it is irrational.