Answer:
a. stereotype.
Explanation:
In sociological context, stereotype refers to an overgeneralized opinion or prejudiced attitude, commonly held by members of a group. A stereotype may be helpful when it helps us to respond quickly to circumstances because we may have had a similar experience before but because it lacks the understanding of individual differences, it sometimes leads to conflicts or biased judgment. As per question, Ruben assumption is based on the stereotype he held about Asian students.
