What can be said of a closed system when an exothermic reaction proceeds in an aqueous solution?

An exothermic reaction is a type of reaction that dissipates heat as the reaction proceeds. This would mean that in a closed system, when a reaction proceeds and is endothermic, the temperature of the solution  or the system would increase so as to maintain the equilibrium with the whole system.

Although the diagram is not shown, i know that the convection is heated by a the core.

The most plausible answer is b, duration. the given amount of time is considered how long it last for.