Endothermic reaction is a type of reaction that absorbs energy during the process. the gauge for this reaction is the change in enthalpy which should be positive. This means the energy of the products should be greater than the energy of the reactants. The graph illustrates an uphill form.
I think the correct answer would be always parabolic. The reaction pathway graph for an endothermic reaction would always be parabolic where the products have higher energy than the reactants. Hope this answers the question.
