According to the passage, alcohol has something to do with bad breath mainly because ______.

A．they can' t mask the bad odor long enough
B．they can' t get to all the offending bacteria
C．their strong smell mixes with bad breath and makes it worse
D．they can' t cover the thick layers of mucus

A．offensive breath can't easily be cured
B．elderly people are less offended by bad breath
C．heavy drinkers are less affected by bad breath
D．offensive breath is less affected by alcohol