A monopoly has produced a product with a patent for the last few years. The patent is going to expire. What will likely happen to the demand for the patent-holder's product when the patent runs out?

Demand for the patent-holder's product will decrease when the patent runs out.

Explanation:

While there is a patent over a product, only the patent-holder's can sell that product. If there is a monopoly it means that that company is the only one that produce and sell this product.

When the patent run out new competitors will enter the business, so the demand on patents holders will decrease.