The best example of something is often called the "gold standard." It sets the standard against which other things are measured. In economics, the term describes how major trading nations once used gold to set currency values and exchange rates. Many nations continued to use the gold standard until the last century. In the United States, people could exchange paper money for gold from the eighteen seventies until nineteen thirty-three. Then-President Richard Nixon finally disconnected the dollar from the value of gold in nineteen seventy-one. From time to time, some politicians call for a return to the gold standard. In 1978, the International Monetary Fund ended an official gold price. The IMF also ended the required use of gold in _ with its member countries. Since that time, gold prices have grown and continued to be high. But people keep buying. Some people are "gold bugs." These are investors who say people should buy gold to protect against inflation . People have valued gold for thousands of years. The soft, dense metal polishes to a bright yellow shine and resists most chemical reactions. It makes a good material for money, political power -- and, more recently, electrical power. If you own a device like a mobile phone or a computer, you might own a little gold in the wiring. The gold standard was the subject of one of the best-known speeches in American political history. William Bryan wanted the country to use both gold and silver as money. The idea was to devalue the dollar and make it easier for farmers to pay their debts. So he delivered a speech, which made him famous. He was a presidential candidate three times. But he never won. After the IMF ended the official gold price, the gold prices  _  .
stayed the same began to drop increased increased a little at first and kept drop
Question: The best example of something is often called the "gold standard." It sets the standard against which other things are measured. In economics, the term describes how major trading nations once used gold to set currency values and exchange rates. Many nations continued to use the gold standard until the last century. In the United States, people could exchange paper money for gold from the eighteen seventies until nineteen thirty-three. Then-President Richard Nixon finally disconnected the dollar from the value of gold in nineteen seventy-one. From time to time, some politicians call for a return to the gold standard. In 1978, the International Monetary Fund ended an official gold price. The IMF also ended the required use of gold in _ with its member countries. Since that time, gold prices have grown and continued to be high. But people keep buying. Some people are "gold bugs." These are investors who say people should buy gold to protect against inflation . People have valued gold for thousands of years. The soft, dense metal polishes to a bright yellow shine and resists most chemical reactions. It makes a good material for money, political power -- and, more recently, electrical power. If you own a device like a mobile phone or a computer, you might own a little gold in the wiring. The gold standard was the subject of one of the best-known speeches in American political history. William Bryan wanted the country to use both gold and silver as money. The idea was to devalue the dollar and make it easier for farmers to pay their debts. So he delivered a speech, which made him famous. He was a presidential candidate three times. But he never won. After the IMF ended the official gold price, the gold prices  _  .
A. stayed the same
B. began to drop
C. increased
D. increased a little at first and kept drop
Answer: