The desired liquid-phase reaction
$D+E\overset{k_{1}}{\rightarrow}F \:\:\:\:\:\:\:\:\:r_{F}=k_{1}\:C_{D}^{2}\:C_{E}^{0.3}$
is accompanied by an undesired side reaction
$D+E\overset{k_{2}}{\rightarrow}G \:\:\:\:\:\:\:\:\:r_{G}=k_{2}\:C_{D}^{0.4}\:C_{E}^{1.5}$
Four isothermal reactor schemes ($CSTR$: ideal Continuous-Stirred Tank Reactor; $PFR$: deal Plug Flow Reactor) for processing equal molar feed rates of $D$ and $E$ are shown in figure. Each scheme is designed for the same conversion. The scheme that gives the most favorable product distribution is:
