a.it has been unpegged from other currencies.
b.the U.S has adopted a hard peg policy.
c.the U.S has purchasing power parity.
d.it has appreciated in terms of other currencies.
d.it has appreciated in terms of other currencies.
Explanation:
Currency appreciation occurs when the value of a currency increases. It leads to increase in demand of the currency against another currency as currencies are traded in pairs or against another currency.
Appreciation of currency is caused by a number of factors such as investments, trade, economic policies, businesses, trad balance, etc.
If the U.S dollar is strengthening then the currency of U.S has appreciated against other currencies.