The correct answer is: C. diesel engines.
Diesel engines are the most common type of engine used to power ships. They are efficient and reliable, and they can be used in a variety of ship sizes and types. Diesel engines work by compressing air and then injecting fuel into the compressed air. The fuel ignites and creates a power stroke that drives the engine.
Nuclear power plants are not commonly used to power ships. They are expensive to build and operate, and they require a lot of fuel. Nuclear power plants are also more complex than diesel engines, and they require more maintenance.
Hydraulic turbines are not commonly used to power ships. They are used in some small ships, but they are not as efficient as diesel engines. Hydraulic turbines work by using the pressure of water to turn a turbine. The turbine then turns a generator, which produces electricity.
Steam accumulators are not commonly used to power ships. They are used in some small ships, but they are not as efficient as diesel engines. Steam accumulators work by storing steam. The steam is then used to turn a turbine, which turns a generator, which produces electricity.
In conclusion, the correct answer is: C. diesel engines.