A first-order liquid phase reaction $A \rightarrow B$ is carried out in two isothermal plug flow reactors (PFRs) of volume $1 \mathrm{~m}^{3}$ each, connected in series. The feed flow rate and concentration of $A$ to the first reactor are $10 \mathrm{~m}^{3} \mathrm{~h}^{-1}$ and $1 \mathrm{kmol} \mathrm{m}^{-3}$, respectively. At steady-state, the concentration of $A$ at the exit of the second reactor is $0.2 \mathrm{kmol} \mathrm{m}^{-3}$. If the two PFRs are replaced by two equal-volume continuously stirred tank reactors (CSTRs) to achieve the same overall steady-state conversion, the volume of each CSTR, in $\mathrm{m}^{3}$, is
- $1.54$
- $3.84$
- $7.28$
- $1.98$