If the price of sweeteners, a complementary good to coffee, decreases, what happens to the price and quantity of coffee?

When the price of sweeteners decreases, it impacts the demand for coffee because sweeteners and coffee are complementary goods; they are often consumed together. A decrease in the price of sweeteners makes them more affordable, which likely encourages consumers to buy more sweeteners. As a result, the demand for coffee also increases, since many consumers will want to purchase more coffee to use the sweeteners with.

This increase in demand for coffee, all else being equal, typically leads to both an increase in the price of coffee and an increase in the quantity of coffee sold. Sellers respond to the greater demand by raising the price to capture more consumer willingness to pay, as well as increasing the quantity supplied to meet that heightened demand.

Thus, the correct answer reflects the dual effect of increased demand: the price of coffee rises, and the quantity sold also rises due to the complementary relationship between coffee and sweeteners.