Why Do Behavioural Assessors Sometimes Set Up Contrived Situations in Which

Why do behavioural assessors sometimes set up contrived situations in which to observe behaviour?

A) They do not think the setting is an important influence on people's behaviour.
B) Such assessments avoid the problem of reactivity.
C) They want to see how people respond in unusual situations.
D) It is often difficult to control the conditions in natural settings.