Final answer:
The first step in calculating the customer defection rate is to define and measure the company's customer retention rate.
Step-by-step explanation:
The correct answer is E. define and measure the company's customer retention rate. The first step in calculating the customer defection rate is to define and measure the company's customer retention rate. By determining how many customers the company is able to retain, it becomes possible to calculate the rate at which customers are defecting.