Coal and Iron Ore Are Complements in the Manufacture of Steel

Coal and iron ore are complements in the manufacture of steel. An increase in the price of coal would lead to

A) an increase in the demand for iron ore as producers substitute more iron ore for coal in the production process.
B) a decrease in the demand for iron ore as steel manufacturers reduce production of steel.
C) an increase in the supply of iron ore as iron ore producers see an opportunity to expand their markets.
D) no change in the demand for iron ore since the steel makers must use both iron ore and coal if they are to make steel.