Country X contains many rivers that flow down from its high mountains. These rivers have been dammed to harness the hydroelectric power that can be derived from this resource. Enough power is generated to create a reserve that is more than enough to meet the country' s year-round energy needs. Yet, citizens of Country X often experience power shortages or even outages. Which of the following, if true, best explains the situation described above? ['The flow of the rivers is heavier in the spring than at other times of year.', 'Most of the electricity generated in Country X is sold to other countries.', 'Citizens of Country X rely heavily on electronic appliances in their homes.', 'Some of the most powerful rivers in Country X have yet to be dammed.']