Why Are Producers Willing and Able to Offer Greater Quantities

Multiple Choice

Why are producers willing and able to offer greater quantities for sale at higher prices?  

A)  because they have the incentive to pay the increasing opportunity cost of resources to attract them from alternative uses 
B)  because they will decrease their profits by expanding production at higher prices 
C)  because lower prices attract new firms, which have higher costs of production 
D)  because they hire superior quality, higher-priced resources as production expands