Answer: a. Hydrokinetic energy is a commonly used form of energy.
Hydrokenetic energy is the renewable source of energy that is produced by the speed currents of water sources, involving the streams of rivers, waves and tides of oceanic water and man-made water channels. This energy is being utilized for generation of electrical energy. Although this process will reduce the dependency of fossil fuel for energy generation. It is not commonly used because it requires high quality expensive turbine system, costly to be implemented in economically less stable regions.