$1)$ Consider an Erlang loss system. The average processing time is $6$ minutes. The average interarrival time is $5$ minutes. The number of servers is $3.$ What is the flow rate in customers per hour?

A$)1\mathrm{.}08$

B$)10\mathrm{.}92$

C$)26\mathrm{.}72$

D$)30$