Final answer:
An appropriate question to ask a customer about their previous experience when assisting them with selecting an item would be b): Have you worn this brand before? What size was most comfortable for you?
Step-by-step explanation:
An appropriate question to ask a customer about their previous experience when assisting them with selecting an item would be:
b) Have you worn this brand before? What size was most comfortable for you?
This question helps gather information about the customer's familiarity with the brand and their previous sizing experience, which can guide the selection process and ensure a comfortable fit.