Which of the following examples best describes the concept of opportunity cost? a.) You like going out to dinner more than staying home to O eat, but this time you choose to stay home and eat leftovers, giving up your higher-valued choice. b.) You find a way to both go to the movies and see your O friend by asking them to join you. O c.) It's a nice day, and you decide to go out for a walk. O d.) You keep losing at a video game with your friend