In an advanced organometallic chemistry research project, a team is investigating the mechanism of a catalytic reaction involving a transition metal complex, 'Complex X', and an organic substrate, 'Substrate Y'. The reaction is crucial for developing a new method of synthesizing a class of organic compounds. The sequence of the investigation is as follows: 'Complex X', which contains a metal with multiple oxidation states, is reacted with 'Substrate Y' under controlled conditions. The reaction mixture is then analyzed using in-situ infrared spectroscopy to monitor the formation of intermediate species. Computational chemistry methods, including density functional theory (DFT), are employed to model the potential reaction pathways and intermediates. Kinetic studies are performed to determine the rate-determining step and the overall order of the reaction. Based on this sequence, what is the primary challenge or objective in the investigation of the reaction mechanism between 'Complex X' and 'Substrate Y'? Options: A. Identifying the catalytic activity and selectivity of 'Complex X' B. Elucidating the stepwise reaction mechanism and intermediate species C. Determining the energy barriers and thermodynamic feasibility of the reaction D. Optimizing the reaction conditions for maximum yield of the product Hints: Consider the purpose of each investigative technique in understanding reaction mechanisms. Reflect on the importance of identifying intermediates and understanding the sequence of steps in a catalytic reaction. Think about how kinetic data and computational modeling contribute to elucidating reaction pathways in organometallic chemistry.