Juanita Petino, a nutritionist, decided to test the effects of two breakfast cereals, Kinglo and Loopy, on different consumer groups. For the purpose of her study, she divided $20$ volunteers into two groups and asked the members of one group to have Kinglo cereal and the members of the other group to have Loopy cereal for breakfast. She decided to compare the responses of the volunteers after a week to gain deeper insights into consumer attitude. In this instance, Juanita is using $\_\_\_\_\_\_\_\_.$

Juanita Petino, a nutritionist, decided to test the effects of two breakfast cereals, Kinglo and Loopy, on different consumer groups. For the purpose of her study, she divided $20$ volunteers into two groups and asked the members of one group to have Kinglo cereal and the members of the other group to have Loopy cereal for breakfast. She decided to compare the responses of the volunteers after a week to gain deeper insights into consumer attitude. In this instance, Juanita is using $\_\_\_\_\_\_\_\_.$

B$)$ experimental research

E$)$ viral marketing

A$)$ niche marketing

C$)$ product differentiation

D$)$ ethnographic research