Answer:
The correct answer is option B. cohort effects.
Explanation:
Cohort effects is an effect that is used in the social science or psychology to explain difference or variations in the traits of part of the study over a period of time in individuals who have some type of similar experiences such as year of birth or age.
It can be understood as a historical event that can lead to affect the cohort due to the life phase it takes place.
Thus, the correct answer is option B. cohort effects.