In a hypothetical reaction, a compound 'X' is converted to 'Y' via a two-step mechanism. The first step is the rate-determining step and involves a transition state similar to 'X'. The second step is much faster and involves an intermediate 'I'. Given the reaction profile, which of the following statements is true? A. The activation energy of the overall reaction is the energy difference between 'X' and the transition state of the first step. B. The energy of the intermediate 'I' is higher than that of 'X' but lower than the transition state of the first step. C. The activation energy of the second step is the difference in energy between 'Y' and 'I'. D. The energy of 'Y' is higher than that of the transition state of the first step.