In which of these situations do the quantities combine to make 0? O A. Scott earns $20 at his family's garage sale. He then earns $20 walking dogs for his neighbors. B. Travis receives $10 from a friend to pay for a concert ticket. He then spends $20 on tickets for his friend and himself. C. A scuba diver drops 30 feet below sea level. He then swims 30 feet across the ocean floor D. A dolphin swims 20 feet straight down from the surface. It then rises 20 feet to return to the surface.