A → D is an endothermic reaction occurring in three steps (elementary).
(i) A → B ΔH_i = +ve
(ii) B → C ΔH_ii = –ve
(iii) C → D ΔH_iii = –ve
Which of the following graphs between potential energy (y-axis) vs reaction coordinate (x-axis) correctly represents the reaction profile of A → D ?