To my opinion the answer is C. Water is an accessible and maintainable resource in the majority of the world. I say this because its definitely not A, or D. It could possibly be B but C gives more information on why so many of the sustainable energy options are water solutions. Hope this helps and that you get the question correct, God bless!
Do uou possible have a picture
Hello There!
A major source of calcium and sodium in oceans is weathering and erosion of rocks.
Option D.
Hope This Helps You!
Good Luck :)
- Hannah ❤