A queuing system has one single server workstation that admits an infinitely queue. The rate of arrival of jobs to the queuing system follows the Poisson distribution with a mean of $5$ jobs per hour. The service time of the server is exponentially distributed with a mean of $6$ minutes. In steady state operation of the queuing system, the probability that the server is not busy at any point in time is

$0\mathrm{.}83$

$0\mathrm{.}17$

$0\mathrm{.}50$

$0\mathrm{.}20$