Energy sustainability can best be achieved by using

If this question has the same set of options like the previous ones, here are the following choices:
a. nonrenewable energy sources        b. renewable energy sources
c. carbon sequestration                       d. recycled plastics

The answer would be: 
Energy sustainability can best be achieved by using renewable energy sources.
>To create a sustainable future, we need to concentrate on renewable energy resources, such as wind power.

Nimbostratus is the correct answer.
explanation: nimbostratus clouds are the type of clouds that are mostly likely present on gray, rainy day. these clouds produce continuous rain, snow and there is no thundering or lightening either.