For an exothermic chemical process occurring in two steps as
i) $\mathrm{A}+\mathrm{B}\to \mathrm{X}$ (slow)
ii) $\mathrm{X}\to \mathrm{AB}$ (fast)
The progress of the reaction can be best described by

For an exothermic chemical process occurring in two steps as;
(i)  $\mathrm{A}+\mathrm{B}\to \mathrm{X}$ (Slow); (ii) $\mathrm{X}\to \mathrm{AB}$ (Fast)
The progress of the reaction can be best described by the graph of option B. Note that after formation of X (a slow process) the decomposition of X is fast; the energy of activation for formation of X is high. ( first peak)

Also, since, the reaction is exothermic, the energy of reactants is higher than the energy of products.

The graph will be as: