Consider a $40-$meter communication link operating at $2Mbps.$ The velocity of propagation in optical fibers is about $2{10}^8\frac{m}{s}.$ A frame of $4000$ bits is sent from a source node to a destination node $($assume the nodes are connected with a direct link$).$ If we send frames continuously over $72$ hours, the probability of receiving $1$ frame in error is: