Answer:
Andrews keeps personal details of customers confidential.
Step-by-step explanation:
Andrew is a salesman and speaks at a fast pace: It is highly difficult for the customer to understand if the sales person talk fast. The customers needs only clear information. So this option is invalid.
He also avoids extending elaborate details about product: Any sales person should give necessary details in order sale the product. So this is also invalid
He dresses casual attire at times: This depicts his personality. Wearing casual attire is the rule and it should be followed all the time and not at times.
Andrews keeps personal details of customers confidential: This is the right option and ethical too.