D) selecting random sample allows for a more representative sample in a survey.
The correct answer is extrinsic motivation.
Extrinsic motivation refers to behavior that is driven by external rewards. In other words, the motivation to engage in a behavior arises from the outside sources because it is naturally satisfying to them. Practically, the behavior is driven by a reward given by someone or something else if the particular thing is done correctly. In this example Brenda is motivated to study more because she wants to earn an A, thus a reward for her effort of studying.
