Which of the Following Is NOT a Policy That Countries

Which of the following is NOT a policy that countries have adopted in the past 100 years?

A) Some countries have given up their own currencies and used another country's currency instead.
B) Some countries have given up their own currencies and created a new shared currency.
C) Some countries have used gold as a currency instead of their own paper currencies.
D) Some countries have kept their own currencies but have tied its value to another country's currency.
E) Some countries have kept their own currencies separate from other countries' currencies.