The MUX plan for a communication system connected $4$ locations namely A$,$ B$,$ C$,$ and D is illustrated below. Giving that the channel cards serve $4$ telephone channels or $6$ data channels. Show how many telephone channels can be added between A and D in each $2$MBPS streams without any additional hardware. How many $2$ MBPS streams can be added between A and C without any additional hardware? Rearrange the channel distribution properly and repeat part $\text{'}$b$\text{'}$