$7\mathrm{.}11.$ Let Xc$($t$)$ be a continuous$-$time signal whose Fourier transform has the property that Xc$($jw$)=0$ for lwl ~ $2,0001$T$.$ A discrete$-$time signal xd$[$n$]=$ Xc$($n$(0\mathrm{.}5$ X $10-3))$ is obtained. For each of the following constraints on the Fourier transform Xd$($ejw$)$ of xd$[$n$],$ determine the corresponding constraint on Xc$($jw $)$: $($a$)$ Xd$($ejw$)$ is real. $($b$)$ The maximum value of Xd$($ejw$)$ over all w is $1.($c$)$ Xd$($ejw$)=0$ for $3$ ; ::; lw I ::; $1$T$.($d$)$ Xd$($ejw$)=$ Xd$($ej$($w$-1$T$)).$