It Is TRUE to Say That the Influenza Virus _________

It is TRUE to say that the influenza virus _________.

A) has not had a deadly outbreak since 1918 because it was a few years before antibiotics were developed
B) has now mutated into a less aggressive form that does not cause any fatalities
C) can become lethal when it mutates into a form that can go undetected by your immune system
D) has remained a looming threat for people with compromised immune systems because it doesn't experience antigenic drift.
E) None of the answers are correct.