Which of the Following Does Not Explain Why Supply Curves

Multiple Choice

Which of the following does not explain why supply curves typically slope upward and to the right:

A) people are willing to pay a higher price for more goods.
B) extra production brings in the less efficient, higher-cost producers.
C) expanded industry output might cause a labor shortage and subsequently a rise in the wage rate and the cost of production.
D) expanded production may require the use of inferior resources.
E) All the above are valid reasons.