When demand decreases and the demand curve shifts to the left, equilibrium price __________ and equilibrium quantity __________ .

A. increases; increases
B. increases; decreases
C. decreases; increases
D. decreases; decreases

When demand decreases and the demand curve shifts to the left, the equilibrium price and equilibrium quantity will both decrease. This can be explained as follows:

In economics, the demand curve represents the relationship between the price of a product and the quantity that consumers are willing and able to purchase at that price. When there is a decrease in demand, it means that consumers are no longer willing and able to buy the same quantity of the product at every price level.

As a result, the demand curve shifts to the left, indicating a decrease in demand across all price levels. This means that at any given price, the quantity demanded by consumers will be lower than before.

Now, let's consider the concept of equilibrium. In a market, equilibrium occurs at the point where the quantity demanded by consumers is equal to the quantity supplied by producers. At this equilibrium point, the market is in balance.

So, when demand decreases and the demand curve shifts to the left, the quantity demanded decreases. In order to restore balance in the market, the price must also decrease. This reduction in price encourages consumers to purchase more of the product, helping to reach a new equilibrium where the quantity demanded and supplied are once again equal.

Therefore, the correct answer is D. decreases; decreases.