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 evaluated to determine whether the market in which the manager exchanges goods and services offers true value. b)They can be used to determine how much an asset can be sold for. c)They can be used to convert different services and commodities into equivalent cash values which can be compared. d)They allow all commodities and services to be assigned a fixed and unchanging value.