Q $1.$ Explain how a source station A and a destination station B

recover from the following error conditions for each of the cases

stated below. State the possible outcomes and how the problem

is resolved in each:

a$.$ A and B are using Go$-$Back$-$N ARQ with $W=7$ and sends

frames $0,1,2,$ and $3$ of which $B$ receives frames $0,1,$ and

$3,$ i$.$e$.,$ Frame$-2$ is lost. B sends REJ$-2$ but REJ$-2$ is lost.

b$.$ A and B are using Go$-$Back$-$N ARQ with $W=4$ and sends

frames $0,1,2,3$ of which $B$ receives frames $0,1,$ and $2,$

i$.$e$.,$ Frame$-3$ is lost in transmission.

c$.$ A and B are using Selective$-$Reject ARQ with W$=4$ and

sends frames $0,1,$ and $2$ of which $B$ receives frames $0$ and

$2,$ i$.$e$.,$ Frame$-1$ is lost in transmission that is detected by B$.$

B sends SREJ$-1$ but SREJ$-1$ is lost.