The interviewer would like to know what you interpret as a fast turnaround when it comes to responding to your customers. You should take note of how quickly you are responded to, by this organization, if you are a past customer. This question also offers the opportunity for you to ask the interviewer what their company policy or expectation may be. You don't want to say '3 days' when it's 24 hours!
"In my current role we have a rule that our inbox needs to be cleared out every three days. So, 72 hours I suppose is the maximum amount of time. With that said, I do try to respond to everyone within 48 hours. Could you share with me your policy?"
"I would love to know what your policy is here. My personal goal is to return all phone messages the same day, and email messages within 48 hours."
"My response time may vary depending on urgency; however, I never leave my clients hanging more than a day. Do you have a preference here?"
"Marketing is fast moving. For that reason, my clients are never left waiting more than a few hours. What is your timeline like here?"
"We have a three-day, unspoken rule, in our company that I follow but I do try to deliver responses a bit faster than that. With that said, I suppose it also depends on the volume of inquiries. In slower times I can return my customers' inquiries within a day. In the holiday season, 72 hours is more reasonable. Is that acceptable for your timeline?"
"My customers often need speedy responses. Between my sales assistant and I, we almost always return inquiries within 8 hours. Could you share with me your expectation here?"
"Parent inquiries need to be answered on the same day, in my opinion. I want my students' parents to know that I care about their questions, and I encourage them."