Concept:Composite supply occurs when different goods can be used as alternatives to satisfy the same want or purpose.
Explanation:The need here is the supply of light.
A candle, a lantern, and a gas lamp are separate products that can each provide light.
Consumers can choose any one of them to satisfy the same need.
These goods are substitutes, not goods produced together from the same source.
Therefore, this is not an example of joint supply.
When several commodities together meet a single want, they form a composite supply.
Answer:D. composite supply.