The correct answer is letter B.
Explanation: Emotional appeal can be made to give the recipient a sense of excitement, joy and happiness, or the opposite: fear and guilt. When there is an appeal to emotion, the irrational aspects are taken into account and the arguments disregarded. Beautiful places, happy people, families having fun causes a positive feeling and motivate consumers to shop.
I believe the answer is: double-blind experiment
In double blind experiments, the subjects that receive the treatment is remained unknown by both the researchers and the subjects until the experiment is finished. The main purpose of double-blind experiment it eliminate the bias of perception that might exist among researchers.