In a Perfectly Competitive Market Buyers Want to Buy 20,000

In a perfectly competitive market buyers want to buy 20,000 units and sellers want to sell 20,000 units of a product when the price is $50 per unit. ABC Corporation, one seller in this market,

A) will sell a fixed number of units regardless of how the price changes.
B) faces a downward-sloping demand curve for its product.
C) will maximize profit by selling at a price less than $50.
D) faces a perfectly elastic demand curve at a price of $50.