Which of the Following Is a Drawback to Having a Common

Which of the following is a drawback to having a common currency across countries,as in the European Union?

A) A common currency increases barriers to trade across countries,reducing opportunities for economic growth.
B) With a common currency,individual countries are no longer able to run independent monetary policies.
C) Having a common currency implies that the prices of goods across countries must always be the same,regardless of consumer preferences for goods across countries.
D) None of the above is a drawback to a common currency.