Government deregulation of the long-distance telephone business has resulted in increased competition among telephone carriers, thus resulting in lower prices for consumers. This process, however, will ultimately result in lower-quality service for consumers, because as the telephone carriers drop their prices to compete with one another for customers, they will be forced to cut corners on non-essential items like customer service. Which of the following, if true, casts the most doubt on the argument that government deregulation of the telephone business will result in lower-quality customer service ？（）
A. Technological advances have decreased the cost of providing long-distance telephone service to less than one-half of its cost prior to deregulation.
B. In a customer survey regarding the electric utility business, another industry that recently went through deregulation, surveyors found that customer dissatisfaction with service was 30 percent higher than prior to deregulation.
C. Customers have listed poor customer service as their number one reason for switching from one long-distance telephone service provider to another.
D. Some companies have decreased the cost of customer service by installing automated telephone response systems that eliminate the need for expensive live employees.
E. The greatest competition for long-distance telephone service providers will come not from traditional telephone companies, but from cellular telephone service providers.