Which of the Following Is not an Assumption of the M/M/1

Multiple Choice

Which of the following is not an assumption of the M/M/1 model?

A) The first customers to arrive are the first customers served.
B) Each arrival comes independently of the arrival immediately before and after that arrival.
C) The population from which the arrivals come is very large or infinite in size.
D) Customers do not renege.
E) Service times occur according to a normal curve.