Describe the business buying process model

How do the different stages of the business buying process model help the buyer manage outcome and consequent risk?
Paper instructions:
Students should take note that the the business buying process model in the first part of the question is described in some detail in the associated chapter from Kotler, P. and G. Armstrong Principles of Marketing.

The second part of the question is designed to test students’ ability to recognise that the business buyer process model is designed to reduce the risk to which customers are exposed. You could say, for example, that such a process enables buyers to choose products that are best suited to the task and thereby reduce the chances of making a wrong purchase. The buying process may also mean that the organisation buys products that are not over-specified (i.e. too good/expensive for the task and as a result money
is not wasted).