To be effective, an item used as money should serve several functions. Select the statement that best describes money's function as a standard of deferred payment. a. That a currency can be used to express the value goods and services that are both relatively expensive and goods and services that are relatively cheap. b. That the purchasing power of a currency is relatively stable over time. c. That people are willing to accept a currency in the future as compensation for debts accrued earlier. d. That a currency is widely accepted in exchange for goods and services and therefore makes economic transactions easier.