Question

what does carter mean when he says conservation is \the cheapest source of energy\?
energy that is not used does not have to be paid for.
alternative sources of energy are cheaper than oil.
conservation makes oil basically free.
energy needs will increase if people conserve more.
done

Explanation:

The phrase "conservation is the cheapest source of energy" refers to the fact that avoiding energy use eliminates the need to spend money on generating, purchasing, or delivering that energy. The other options are incorrect: alternative energy sources have their own costs, conservation does not make oil free, and conservation reduces (not increases) energy needs.

Answer:

A. Energy that is not used does not have to be paid for.