When the price of muffins increases, the demand for coffee is likely to ______, indicating that these goods are complementary.

When the price of muffins goes up, people may buy fewer muffins. Since muffins and coffee are complementary goods, meaning they are often enjoyed together, this can lead to a decrease in the demand for coffee as well. For example, if someone usually buys a muffin and a coffee for breakfast, a higher price for muffins might make them decide to skip the muffin and not buy the coffee either. This shows that when the price of one good increases, it can affect the demand for another good that is usually purchased alongside it. Therefore, as the demand for muffins decreases, the demand for coffee is likely to decrease too.