Question #$2(40$ pts$)$: The following equations describe the input$/$output relationships of different systems

System A: $()=(),0$ System B: $()=(2)$ System C: $[]=3[]$

System D: $[]=[]+,,0$ System E: $[]=[]=$

For each of these systems A$,$ B$,$ C$,$ D and E$,$ determine whether it is

$($i$)$ linear, $($ii$)$ time$-$invariant, $($iii$)$causal$,($iv$)$stable by explaining the reasons of your choices.