Mountaineers Say That You Cannot Hardboil an Egg on the Top

Multiple Choice

Mountaineers say that you cannot hardboil an egg on the top of Mount Rainier.This is true because

A) the air is too cold to boil water.
B) the air pressure is too low for stoves to burn.
C) boiling water is not hot enough to hardboil the egg.
D) the oxygen content of the air is too low.
E) eggs always break in their backpacks.