Final answer:
The correct response is to ask if the customer wants whip cream on their beverage despite requesting non-dairy milk, as whip cream typically contains dairy. It also helps to inform them about the dairy content of the whip cream.
Step-by-step explanation:
If someone orders a beverage that comes with whip cream, and they ask for a non-dairy milk, it is important to ask if they want the whip cream on top. Since whip cream is traditionally made from dairy, a customer requesting non-dairy milk might also want to avoid dairy in other parts of their beverage, but they also might still want the whip cream regardless of its dairy content. Therefore, the correct answer is A: If they want the whip cream on top. Additionally, it's good practice to inform the customer that the whip cream does contain dairy in case they are trying to avoid it due to allergies or dietary preferences.