Beginning in the 1960s, social psychologists found compelling evidence that the presence of other people and the environment one was in, collectively known as the __________, was primarily responsible for eliciting a person's behavior.

A) personal environment
B) collective space
C) bystander effect
D) situation

The phrase "presence of other people and the environment one was in" suggests that the answer is referring to a specific context, rather than a person's individual surroundings (A) or a vague concept like "collective space" (B). Additionally, the phrase "bystander effect" refers to a specific phenomenon within social psychology, rather than being a general term for the context that influences behavior. Therefore, the best answer is D, situation.