It has been found that for a chemical reaction with rise in temperature by $9 \mathrm{K}$ the rate constant gets doubled. Assuming a reaction to be occurring at $300 \mathrm{K}$, the value of activation energy is found to be ${\mathrm{kJmol}}^{-1}$. [nearest integer] (Given $\ln 10=2.3,\mathrm{R}=8.3 \mathrm{J}{ \mathrm{K}}^{-1}{ \mathrm{mol}}^{-1},\log 2=0.30$)

Hence, the correct answer is 59.