The First Full-Fledged Gold Standard

The first full-fledged gold standard

A) was not established until 1821 in Great Britain, when notes from the Bank of England were made fully redeemable for gold.
B) was not established until 1780 in the United States, when notes from the Continental Army were made fully redeemable for gold.
C) was established in 986 during the Han dynasty in China.
D) none of the above