$1\mathrm{.}4-8$ Maximum end$-$end throughput $($e$).$ Consider the scenario below where $4$ TCP senders are connected to $4$ receivers. Servers $1-3$ transmit to the receiving hosts at the fastest rate possible $($i$.$e$.,$ at the rate at which the bottleneck link between a server and its destination is operating at $100\%$ utilization, and is fairly shared among the connections passing through that link$).$ Server $4$ has nothing to send, so its sending rate is zero mUSt$-$L Suppose that R$=1$ Gbps$,$ R$\_$C is $300$ Mbps and R$\_$S is $400$ Mbps$.$ What is the TCP throughput achieved on each of the $3$ sctive$-$sending connections?a$.$ R $/4$ b$.$ R$\_$S c$.4$ R d$.$ R e$.$ R$\_$c