Read and choose the best answer.
If you're looking for ways to improve your products or services, customers can be one of your most valuable sources of information and market research. So why not take it a step further and visit some of them?
    Ideally, you want to do this in person, so you may need to offer your customers something for their time. They may be pleased that you take their opinion seriously, and they may also enjoy getting a chance to help influence your products or services. If your customers are in different places, you could make such visits part of your business travel to get a wider range of responses.
    One expert recommends that you make your customers feel comfortable during the visits. You're not trying to sell anything through these meetings, so plan to spend 80 percent of your time listening.
     Don't try to lead your customer to give responses that you really want to hear. Instead, ask questions that focus on the customer's experience, such as whether they got what they were hoping for and what they found difficult or enjoyable.
 
According to the passage, your customers can be very helpful in __________.
A、expanding your business
B、reducing your production cost
C、selling your products or services
D、improving your products or services