单选题 The total cost for Company X to produce a batch of tools is $10,000 plus $3 per tool. Each tool sells for $8. The gross profit earned from producing and selling these tools is the total income from sales minus the total production cost. If a batch of 20,000 tools is produced and sold, then Company X's gross profit per tool is
(A) $3.00 (B) $3.75 (C)$4.50
(D) $5.00 (E) $5.50

【正确答案】 C
【答案解析】[解析] 公司X生产20,000件工具的总成本是:10,000+20,000×3=70,000美元;这20,000件工具的销售收入为:20,000×8=160,000美元,所以每件工具的毛利润为: