Answer & Explanation
A resource is a source or supply from which a benefit is produced. Resources can be broadly classified upon their availability they are renewable and non renewable resources.
Renewable Resources :: A resource that can be replenished after use are known as Renewable resources.
Examples :: Sunlight, Water, biomass,...
Non renewable Resources :: A resource that, once used, is no longer available are known as Non renewable Resources.
Example :: Coal, fossil fuels, natural gas,...
Sunlight is the both renewable and inexpensive resource from the given options.