Hi, I was confused about what the question was asking for.
Potential energy is due to positions and when a spring is compressed or stretched or a stone on the a height or water is stored in dam then there is an increase in potential energy.
Increase in attraction is decrease in potential because more attraction means less energy. Decrease in attraction means increase in potential energy because it means high energy. So when opposite charges are coming closer than potential energy is decreasing as attraction is increasing. When opposite charges are separated then it is increase in potential energy.
All reactions which are endothermic are also with increase in potential energy because energy is gained and energy of the product is higher than that of the reactant.(Remember the graph) However exothermic reactions are the one in which energy of the products is less than that of the reactant and is the one which shows decrease in potential energy.
Remember all combustion reactions(one reactant is oxygen gas) are exothermic. Identify which reaction here is exothermic and that will be the answer.
Thank you, that makes sense now.