If Everything Else Remains Constant,including the Mean Arrival Rate and Service

If everything else remains constant,including the mean arrival rate and service rate,except that the service time becomes constant instead of exponential,

A) the average queue length will be halved.
B) the average waiting time will be doubled.
C) the average queue length will be doubled.
D) There is not enough information to know what will happen to the queue length and waiting time.
E) None of the above