Question

Which stament about energy is mostly correct

Answer 1

I would say C is the most correct. 
In D it depends on what water source you're using. Let's say it is a waterfall, then the source of the water (melting ice or a lake) may disappear in the future. 
If you're using underwater "windmills" placed in the ocean, then you would expect it to last a while as the ocean will not disappear in the near future.