Consider the reaction \[A\to 2B+C,\Delta H=-15\]kcal. The energy of activation of backward reaction is\[20\text{ }kcal\text{ }mo{{l}^{-1}}\]. In presence of catalyst the energy of activation of forward reaction is \[3\text{ }kcal\text{ }mo{{l}^{-1}}\]. At 400 K. the catalyst causes the rate of the reaction to increase by the number of times equal to

• A. \[{{e}^{3.5}}\]
• B. \[{{e}^{2.5}}\]
• C. \[{{e}^{-\,2.5}}\]
• D. \[{{e}^{2.303}}\]