Joe sold gold coins for $1,000 that he bought a year ago for $1,000. he says, "at least i didn't lose any moncy on my financial investment." his economist friend points out that in effect he did lose moncy because he could have received a 3 percent return on the $1,000 if he had bought a bank certificate of deposit instead of the coins. the cconomist's analysis in this case incorporates the idea of a. opportunity costs b. marginal benefits that exceed marginal costs. c. imperfect information. d. normative economics