The drain$-$to$-$source saturation current $($lDSS$)$ and the pinch$-$off voltage for an $n-$channel depletion type MOSFET are $10$mA and $-4$V$,$ respectively. Draw the transfer characteristics of the transistor by showing the enhancement and depletion modes. How would you explain those transistor modes from the plot? $[10$p$]$