Answer:
e) energy returned divided by energy invested.
Step-by-step explanation:
When assessing energy resources, it is helpful to use a measure called Energy Returned On Investment (EROI), which is energy returned divided by energy invested.
Energy Returned On Investment (EROI) is a means of measuring the quality of an energy source.
Generally, EROI can be defined as the ratio of the quantity of usable energy (exergy) gotten from a specific energy resource to the quantity of energy used to produce that energy resource.
Some examples of energy resources are fossil fuel, solar, hydropower, wind, nuclear, tidal, hydrogen, wave etc.