The correct answer is C. 1914.
Bimetallism is a monetary system in which the standard economic unit of account is based on two metals, typically gold and silver. Under bimetallism, the standard economic unit of account is divided into a fixed number of parts, each of which is represented by one of the two metals. The relative values of the two metals are determined by the market, and the government guarantees to convert any amount of one metal into the other at the fixed rate.
Bimetallism was the dominant monetary system in Europe and the United States for centuries. However, it began to decline in the 19th century, as the supply of gold and silver increased and the two metals became increasingly difficult to keep at a fixed ratio. The United States abandoned bimetallism in 1873, and most other countries followed suit in the late 19th and early 20th centuries.
The concept of bimetallism, with gold and silver full-bodied coins in circulation continued up to the year 1914. In that year, the outbreak of World War I led to a sharp increase in the demand for gold, and most countries suspended the free coinage of silver. After the war, most countries returned to a gold standard, and bimetallism was abandoned.
Option A is incorrect because bimetallism was still in use in 1857. Option B is incorrect because bimetallism was still in use in 1875. Option D is incorrect because bimetallism was abandoned in 1914.