Answer:
I would go with C) food because food gives us energy, healthy veggies give us energy and unhealthy junk food really doesn't give us as much energy and makes us fat. Not air because air is the need for life, not energy, and not a place to live since that really doesn't give us energy. It's not water, although we can't live after a few days without water due to dehydration, water does not give us energy it just keeps our bodies and living things hydrated.
I hope this helps you :)