Answer: Fundamental Attribution Error
Explanation: Marilyn made this mistake, which many people make, which is that she overemphasised the professor's behaviour, where the cause of such professor's behaviour is his personal reason, often by such people as Marilyn is seen as a "psychological problem" of a personal nature, and not as behaviour for objective, professional reasons. In doing so, Marilyn evaluated the cause of the professor's behaviour solely on the basis of observation of his behaviour, i.e on the basis of perceptual visibility, and not on some additional information that would provide further insight into the professional, therefore not personal, reasons for such behaviour.
Such an assessment of others is also called cognitive bias, so a person's behaviour depends on the "type" of the person, i.e whether the person is strict, old-fashioned, and not on social or objective circumstances, and therefore such an assessment is biased, like Marilyn's assessment of the professor's personality that he is rigorous means that Marilyn's assessment is biased.
