In the Context of Marketing Research,what Is Meant by an Experiment

In the context of marketing research,what is meant by an experiment?

A) It is a method in which the researcher gains information on attitudes, opinions, or motivations by questioning current or prospective customers.
B) It is a process in which researchers can elicit a full range of responses from people and thereby infer how well advertising messages convey key copy points.
C) It is a method in which test commercials are shown with noncompeting control commercials to determine their effectiveness, measure comprehension and attitude shifts, and detect weaknesses.
D) It is a scientific investigation in which a researcher randomly assigns different consumers to two or more messages or stimuli.
E) It is an investigation in which respondents are shown test commercials, usually in shopping centers, and questions are asked before and after exposure.