What Type of Research Design Should Be Used to Obtain

Multiple Choice

What type of research design should be used to obtain conclusive answers to questions such as why sales increase or decrease if we increase or decrease advertising,why one ad garners greater attention and recall than another,and why $0.50 coupons make people buy the national brand versus the store brand?

A) Exploratory
B) Causal
C) Descriptive
D) Case Analysis
E) All of these are correct.