Answer:
A
Step-by-step explanation:
One of the main complaints about hydropower is that it will change the ecosystem. You can read about the history of any dam and you will find that most of them have involved evacuation. That means that farmland was lost and replaced by a lake behind the dam. The energy comes from water cascading over the top of the dam to its bottom.
It does not produce radiation.
It does not burn fossil fuels. It's clean and does not pollute the air.
So there are no greenhouse gases involoved.