Oil refiners can refine a barrel of petroleum so that it yields either more home heating oil or more diesel fuel. If the price of diesel fuel falls, there is

A$.$ an increase in the demand for home heating oil.

B$.$ a decrease in the quantity of home heating oil supplied. $($how is b wrong?$)$

C$.$ an increase in the quantity of home heating oil supplied.

D$.$ an increase in the supply of home heating oil.

E$.$ a decrease in the supply of home heating oil.