单选题

Three firms operate under perfect competition, producing 900 units of the same product but using different production technologies. Each company's cost structure is indicated in the table:

Company	X	Y	Z
Total Variable Costs	$2,700	$3,600	$4,500
Total Fixed Costs	2,700	1,800	900
Total Costs	$5,400	$5,400	$5,400

Which of the following statements is most accurate? If the unit selling price is:

A、 $4.50, all firms should continue to operate in the short run, but exit the market in the long run if these conditions are expected to persist.
B、 $3.00, Firm X should continue to operate in the short run, but Firms Y and Z should shut down production.
C、 $6.00, all firms should exit the market in the long run.

【正确答案】 B

【答案解析】