Water in an open container boils at a lower temperature when heated at the top of a mountain than at sea-level because at the top of a mountain

A.

pressure is increased

B.

pressure is reduced

C.

the rays of the sun add more heat to the water

D.

the saturation vapour pressure of water is higher than at sea-level

E.

the temperature is lower than at sea-level

Correct answer is B

No explanation has been provided for this answer.