Robin, a 28 year old fashion designer, is very finicky about the brands that she consumes as a customer. She believes buying brands that she previously used. When Robin walks into Brown and Grey, a supermarket, she is most likely to engage in to buy toothpaste and mouthwash.
A) cognitive dissonance
B) an evaluation of alternatives
C) an internal information search
D) impulse buying
E) business to business marketing

C) an internal information search

Explanation:

There is a model related to consumer decision making. There are several steps to it.  

The first step is  

Information search: We think that what are the alternatives or another way to solve the problem. For example, you will buy a new car, repair your car, drive a bus or ride a bicycle to reach your work.  

Thus here Robin used internal information research to buy toothpaste or a mouthwash.

answer; (b) knowledge based summaries of our beliefs and feeling about the self in particular domains;