Today you are planning to see a movie, and you can attend either of two theatres. You have only a small budget for entertainment, so prices are important. You have attended both theatres recently. One charged $10 for admission; the other charged $11. You habitually buy popcorn in the theatre—each theatre charges $5. The movies now being shown are equally attractive to you, but you are virtually certain that you will never see the movie that you reject today. Identify the relevant costs. Explain your answer.