:a decline in the value of a currency.
a. rise
b. importation
c. depreciation
d. appreciation
a. gold standard
b. fixed exchange rate
c. currency calculation
d. floating exchange rate

by using  production possibilities graph.  opportunity costs are key expenses in financial matters and are utilized as a part of registering money saving advantage investigation of a venture. such expenses, be that as it may, are not recorded in the record books but rather are perceived in basic leadership by processing the money costs and their subsequent benefit or misfortune.