Ashley bought a 2.5 liter helium balloon at the mall and put the balloon in her car for several hours while she continued to shop. When Ashley bought the balloon, the temperature inside the mall was 22.0°C. When Ashley returned to her car several hours later, the
temperature in her car was 4.0°C. What happened to Ashley's
balloon while inside her car?
A. The balloon expanded.
B. The balloon melted.
C. The balloon was the same.
D. The balloon's volume decreased.
(Why is your answer right?)