Answer: C. energy returned divided by energy invested.
Explanation:
The Energy Return on Investment (EROI) simply means the ratio of the amount of usable energy that is obtained from a particular resource to the amount of the energy that is being expended in order to produce the net amount of the energy.
When assessing energy resources, it is helpful to use a measure called EROI and this is the energy returned divided by energy invested.
Therefore, the correct option is C
