A Decrease in the Equilibrium Price and an Increase in the Equilibrium

A decrease in the equilibrium price and an increase in the equilibrium quantity in a market would be caused by:

A) a decrease in the number of sellers in the market.
B) an increase in the number of buyers in the market.
C) an increase in the popularity of the product sold in the market.
D) a decrease in the cost of producing the product sold in the market.