With a single-server model, increasing the arrival rate by 10 percent and also increasing the service rate by 10 percent will result in:

a. an increase in both the average number of customers in the system, and the average wait time.

b. a decrease in both the average number of customers in the system, and the average wait time.

c. no change in the average number of customers in the system, but a decrease in the average wait time.

d. no change in either the average number of customers in the system, or the average wait time.