Although Helpful, the Generic Model of the Buying Decision Process

Although helpful, the generic model of the buying decision process does not completely explain how purchase decisions are made for all customers in all instances. This is because

A) routine purchases do not follow the rational decision-making model.
B) self-concept theory is in clear opposition to the model.
C) there are many contributing variables and the ones that actually trigger a response cannot always be readily determined.
D) the steps of the generic model cannot be accomplished by any single individual.
E) the model does not consider the hierarchy of needs.