Concept:Solar energy is widely regarded as the most environmentally friendly because it produces no direct pollution during use.
Explanation:Solar energy is a renewable source that does not release greenhouse gases while generating electricity.
Solar panels can be mounted on rooftops, so they do not require extra land or cause habitat loss.
Hydroelectric power is also renewable, but constructing dams can harm aquatic life and disturb local ecosystems.
Thermal energy often depends on burning fuels, which emits smoke and carbon dioxide.
Nuclear energy generates radioactive waste, which remains hazardous for many years.
Among all four options, solar has the smallest negative impact on the environment.
Answer:D. Solar