Which statement correctly compares the boiling point of water on a mountaintop with the boiling point of water at sea level?
A. The boiling point of water is lower on the mountaintop because
the temperature is lower.
B. The boiling point of water is lower on the mountaintop because
the air pressure is lower.
C. The boiling point of water is higher on the mountaintop because
the air pressure is higher.
D. The boiling point of water is higher on the mountaintop because
the temperature is higher.