Joint supply: Goods produced together from the same process

Steps:

• Recall that joint supply involves multiple products emerging simultaneously from one production activity.
• Identify examples like beef and leather from cattle, where supply of one affects the other.
• Distinguish from separate production choices or consumer preferences.
• Match the definition to option C, which describes by-products.

Why C is correct:

• Joint supply is defined in economics as the simultaneous production of two or more goods from a single process, where one good is a by-product of the other, like wool and mutton from sheep.

Why the others are wrong:

• A describes joint production or product differentiation, not joint supply.
• B is unclear and confuses multiple uses with joint output.
• D refers to complementary goods in demand, not supply-side production.

Final answer: C