Answer:
A.
Step-by-step explanation:
The energy is absorbed by the water, it means that the system is losing heat, so, the difference of energy must be negative, the initial energy must be higher than the final energy.
For the reaction happens, the reactants must gain energy to overtake the activation energy, and for that, the reaction can occur.
Only letter A represents a system that the final energy is higher than the initial, and the system gains energy at the beginning.