Which of the Following Patients Exhibits an Acceptable Ventilatory Demand

Which of the following patients exhibits an acceptable ventilatory demand? $\begin{array}{ll}&\mathrm{V}_{\mathrm{E}}&\mathrm{PaCO}_{2}\\A.&14 \mathrm{~L} / \mathrm{min} & 40 \mathrm{~mm} \mathrm{Hg} \\B.&12 \mathrm{~L} / \mathrm{min} & 48 \mathrm{~mm} \mathrm{Hg} \\C.&8 \mathrm{~L} / \mathrm{min} & 36 \mathrm{~mm} \mathrm{Hg} \\D.&15 \mathrm{~L} / \mathrm{min} & 35 \mathrm{~mm} \mathrm{Hg}\end{array}$