Gold Is Sold in World Markets, Usually Priced in Terms

Gold is sold in world markets, usually priced in terms of troy ounces. In the market for gold, the price elasticity of demand for gold would be expressed as

A) the number of troy ounces of gold sold.
B) the number of whatever currency is used in purchasing the gold.
C) the number of dollars spent on gold.
D) a unitless number.