Customers arrive at a suburban ticket outlet at the rate of 16 per hour on Monday mornings (exponential interarrival times). Selling the tickets and providing general information takes an average of 3 minutes per customer and varies exponentially. There is 1 ticket agent on duty on Mondays.

What is the average number of customers waiting in line?

A) 1.633

B) 2.333

C) .25

D) 3.966

E) .2