Answer:
The answer is C. In order to carefully control conditions and confirm or disconfirm a hypothesis about the causes of behavior, one must perform an experiment.
Step-by-step explanation:
Experimental research allows the researcher to control all the variables in order to create the conditions that can confirm or disconfirm a hypothesis. This method aimes to establish a relation of causality between two variables, which means that one variable is generated and determined by the other; this is posible because all of the other variables that can influence it have been controlled.
When a researcher conducts a survey or engages in naturalistic observation, he can't control the variables, therefore, he can only establish a correlation between two variables, but not of causality.