Much Like What Probably Happened with the Germ That Now

Much like what probably happened with the germ that now causes the common cold, cholera has evolved a new strain (El Tor) that:

A) is more fragile than the classic/original strain is after leaving the human body.
B) is much deadlier than the classic or original strain.
C) is less deadly than the classic or original strain.
D) is likely to emerge as a pandemic threat.
E) is zoonotic.