[单项选择]The ratio between payments into and out of a country is known as the country’s balance of payments. Besides the value of imports, and exports (the balance of trade), the balance of payments includes private foreign loans (and interest); loans by governments, central banks, and international organizations; and movements of gold or reserve currencies.
An international medium of exchange is required for international trade. From the late 1800s until World War Ⅰ, most countries operated on the gold standard. Gold coins of standard specifications circulated freely between countries, making gold in effect an international currency. This system provided an automatic correction for some trade imbalances, but it had little liquidity (the money supply could not expand as rapidly as required by expanding trade), and it was vulnerable to short-term changes in the gold supply.
After the financial instability of the 1930s, the international monetary(货币的) system was rebuilt following
A. it does not establish a generally accepted international medium of exchange
B. it establishes no relationship between the value of a given currency and the value of gold
C. the relationship it established between the value of any currency and the value of gold is indirect rather than direct
D. it is a two-tiered rather than a single-tiered system