Correct option is D
The queueing model is M/G/1.
Formula Used:
In Kendall's notation:
M = Markovian (Poisson arrivals or exponential inter-arrival times),
G = General (arbitrary service time distribution),
1 = One server (single channel).
Solution:
the inter-arrival times are exponentially distributed,
the service time distribution is arbitrary,
and there is a single server.
Hence, all the given statements are correct.
The correct answer is (d) All of these.