At a telephone enquiry system the number of phone calls regarding relevant enquiry follow Poisson distribution with an average of 5 phone calls during 10 minute time intervals. The probability that there is at the most one phone call during a 10 minute time period, is :

Question

( A ) $\frac{5}{6}$
( B ) $\frac{6}{e^5}$
( C ) $\frac{6}{5^e}$
( D ) $\frac{6}{55}$