Question

the supply curve usually: is horizontal. is vertical. slopes upward. slopes downward.

Explanation:

The law of supply states that, ceteris paribus, as the price of a good or service increases, the quantity supplied increases. This results in an upward - sloping supply curve. A horizontal supply curve implies perfectly elastic supply, a vertical one implies perfectly inelastic supply, and a downward - sloping curve would violate the law of supply.

Answer:

C. slopes upward