The answer here is , A. Thermal energy
Earth’s global temperature has changed greatly in the past hundreds of years. This is due to how much energy the planet is receiving from the sun and how it radiates back. Another cause is humans, due to deforestation, burning of fossil fuels, pollution, etc.
The answer to this question is A. A simple Google search will help you find the answer. But, straightforward. That's what he stated in the document he made as the third law. So, that's the answer. Period.
