Evaporation is a surface phenomenon.

$$\begin{gathered} \mathrm{A}: 3.0 \times {10}^4 {\mathrm{JKg}}^{-1} \\ \mathrm{B}:3.35 \times {10}^5 {\mathrm{JKg}}^{-1} \\ \mathrm{C}: 3.35 \times {10}^{10} {\mathrm{JKg}}^{-1} \end{gathered}$$

(Enter your correct answer as $\mathrm{A}, \mathrm{B} \mathrm{or} \mathrm{C}$)