Customers Arrive According to a Poisson Distribution

Multiple Choice

Customers arrive according to a Poisson distribution. The average number of customer arrivals per hour is four. The probability that three customers will arrive in the next two hours is:

A) less than or equal to 0.015.
B) greater than 0.015 but less than or equal to 0.020.
C) greater than 0.020 but less than or equal to 0.025.
D) greater than 0.025.