In which of these situations do the quantities combine to make 0?
O A. In the morning, the temperature rises 30 degrees. In the evening, it
falls by 30 degrees.
B. Kathy receives $20 as a gift. She gives half of her $20 to a friend
and keeps the rest for herself.
C. A hot air balloon rises 40 feet. It then rises another 40 feet.
O D. A player in a game earns 4 points for getting an answer right. She
then earns 4 points for making it around the board.