Final answer:
The best response would be to apologize and explain to the customer that the bath towels have not arrived but are expected in the morning. Therefore, the correct option is D.
Step-by-step explanation:
The best response in this situation would be to apologize and explain to the customer that unfortunately the towels have not arrived but are expected in the morning. This shows empathy towards the customer's frustration and provides them with accurate information about when the bath towels will be available. It is important to maintain a friendly and professional tone when communicating with the customer.