The correct answer is (D).
Decomposition is the process by which organic matter is broken down into smaller molecules by bacteria, fungi, and other microorganisms. This process is essential for the recycling of nutrients in the environment.
Solar energy is a type of renewable energy that comes from the sun. It can be used to generate electricity, heat water, and power vehicles.
Hydroelectric power is a type of renewable energy that uses the power of moving water to generate electricity.
Elevated temperatures are temperatures that are higher than normal. They can be caused by natural processes, such as volcanic eruptions, or by human activities, such as burning fossil fuels.
In the context of the question, decomposition is the correct answer because it is the process that transforms organic material into hydrocarbons. The other options are not correct because they do not involve the transformation of organic material into hydrocarbons.