$7)$ Two nodes A and B in a local area network $($LAN$)$ transmit frames

of $1000-$bits. The transmission time and the propagation time

between two nodes is $0\mathrm{.}01$ ms and $0\mathrm{.}495$ ms respectively.

If the stop$-$and$-$wait flow control protocol is used between nodes A

and B$,$ the maximum line utilisation will be:

$($a$)9\%($b$)10\%($c$)90\%($d$)1\%$