A sample of milk splits after

A sample of milk splits after $60 \mathrm{~min}$. at $300 \mathrm{~K}$ and after $40 \mathrm{~min}$. at $400 \mathrm{~K}$ when the population of lactobacillus acidophilus in it doubles. The activa tion energy (in $\mathrm{kJ} / \mathrm{mol}$ ) for this process is closest to

(Given, $\mathrm{R}=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}, \ln \left(\frac{2}{3}\right)=0.4$,

$\left.e^{-3}=4.0\right)$