If $\lambda$ = 6 CUSTOMERS/HOUR And $\mu$ = 11 CUSTOMERS/HOUR, in a Single Server Model, Find the in a Single

If $\lambda$ = 6 CUSTOMERS/HOUR and $\mu$ = 11 CUSTOMERS/HOUR, in a single server model, find the probability that there will be exactly 1 person in LINE.

A) 0.162
B) 0.297
C) 0.248
D) 0.135