Alcohol is seldom used as an antifreeze because___________.

A．to help to sell antifreezes
B．to explain what antifreezes are
C．to compare ethylene glycol with alcohol
D．to tell what kind of antifreeze to choose

A．can prevent ice from melting
B．keep alcohol from boiling away
C．keep water from freezing in very cold water
D．can raise the freezing point of water