An endothermic reaction with high activation energy for the forward reaction is given by the diagram:

An endothermic reaction is one in which the potential energy of the products is greater than that of the reactants ($\Delta H>0$). High activation energy means the energy barrier (peak) between reactants and products is very large. Diagram (c) correctly illustrates a large increase in potential energy from reactants to products with a very high activation energy barrier.