The best method to understand the causal effect of a reward on an intrinsically motivated behavior is to

Explanation:

Intrinsic motivation can be define as the behavior which is driven by the internal rewards. This is based on self motivation and the person give himself or herself the reward after accomplishment of a short goal or task.

The best method to understand the effect of reward on the intrinsic motivation is to conduct an experiment in which the intrinsic motivation in the behavior can be tested without any reward and observing the sense of motivation and observing other condition in which one gives himself or herself a reward to motivate ownself.

answer; /// i do believe that the correct answer is (d) cooperative play; /// good luck