Which of the following best explains why market prices are useful to a financial manager when performing a cost-benefit analysis（）
A. They can be used to determine how much an asset can be sold for
B. They can be used to convert different services and commodities into equivalent cash values which can be compared
C. They allow all commodities and services to be assigned a fixed and unchanging value
D. They can be evaluated to determine whether the market in which the manager exchanges goods and services offers true value
What is the bid-ask spread（）
A. the difference in price available for an immediate sale of a stock and the immediate purchase of the stock
B. all of the costs and fees that a stock exchange charges in order to process a transaction
C. the rise or fall in the value of a stock between the time it is acquired by an investor and sold by that investor
D. the difference in the selling price of a stock between different exchanges
Which of the following statements is true（）
A trader is a market maker
B. A trader operates in a foreign exchange trading room
C. A trader is also a broker
D. None of the other statements
下列属于面肌的有（）
A. 眼轮匝肌B:口轮匝肌
B. C．提上唇肌
C. D．降口角肌
D. E．颊肌
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