To increase the sales representatives' product knowledge, the sales director arranges for each of them to rotate through the product development department for a month to understand the way the chemicals are developed. What is another department they should rotate through to gain more product knowledge that will help them configure the right mix of products for customers

A. customer service, so that they can learn how the chemicals are implemented and used by the customer
B. logistics, so that they can understand how the products are delivered
C. billing, so that they understand the problems that arise when customers do not pay promptly
D. warehousing, so they can understand exactly how much room the chemicals take up in storage
E. human resources, so they can understand what characteristics a successful salesperson should have