Why did the U. S. dollar became important to economies around the world in the mid-20th century

The U.S. Dollar became important to economies around the world in the mid-20th century as the relative strength of the U.S. economy is in favor of the value of the U.S. dollar.

Explanation:

The U.S. Dollar became important to economies around the world in the mid-20th century as the relative strength of the U.S. economy is in favor of the value of the U.S. dollar. Also, U.S. dollar can also be used as hard currency in day-to-day transactions.  According to the International Standards Organization List, the dollar is one of the world's 185 currencies. Approximately, 90% of forex trading involves the use of the U.S. dollar.

can you post options?

the answer is b: an economic crisis throughout the country.