Q$4)$ Suppose there are two packet switches in between a sender A$,$ and a receiver B$.$ A is sending a packet that is $1500$ bytes long. The propagation speed on all three links is $2\mathrm{.}5*10^8$ m$/$s$,$ the transmission rates of all three links are $2\mathrm{.}5$ Mbps$,$ the packet switch processing delay is $3$ msec, the length of the links are $3000$ km$,2000$ km and $5000$ km$.$What is the end$-$to$-$end delay of the packet originating at A destined for B$?(2$pt$)$