Answer the following question given this paragraph: 

Any organic material can be made into electricity. But some materials are better than others. Wastes can be used, like almond shells. Biomass power is a great use of wastes. It's hard to use wastes as a consistent large scale source of energy though.


Q: What kind of material that might otherwise go to a landfill can serve as the source of biomass power?

 Choices:

- mechanical waste

- microscopic waste

- reactive waste

- organic waste

A:
organic waste
