What Is the First Step to Take When Segmenting End-Users

What is the first step to take when segmenting end-users by service outputs?

A) dividing end-users into groups based on demographic factors
B) analyzing the buying habits of potential end-users of a product
C) identifying similar characteristics among the product's end-users
D) listing service outputs that are potentially demanded by the product's end-users
E) providing relevant information on service outputs to potential end-users of the product