At present, people obtain electricity by building dams on rivers, but there are only a few places on the earth that are suitable for dams, and dams will also damage the ecological environment. In contrast, the surface of the earth covered by the ocean. There is huge energy around the clock, and the collection of wave energy is suitable for a wide range of seas with little damage to the ecological environment. Therefore, collecting wave energy for power generation is more advantageous than generating dams on rivers. Which of the following cannot be questioned if it is true? ['It is estimated that the wave energy that can be developed and used in the world reaches 2.5TW. At present, some low-power wave energy equipment has been promoted for navigation buoys, lighthouses, etc.', 'The flow direction of the river is relatively stable, and the wave is a slow movement of the sea water, the direction is not fixed, and the efficiency of the generator set up under this condition is very low.', 'Whether it is to build a tower on the sea floor to support power generation, or to fix a generator on the sea floor, it will cost a lot of money, and the cost is much more expensive than a river power station.', 'The water energy of the river is easy to collect, but the wave energy in the deep sea and the open ocean is difficult to extract, and the available wave energy is limited to the coast.']