Use the Following Information to Answer the Questions Below

Use the following information to answer the questions below.
Throughout history, human populations have been impacted by viral outbreaks. In the past 100 years we have seen several devastating epidemics and pandemics that have put people at risk. Worldwide, annual seasonal flu epidemics result in about three to five million cases of severe illness, and about 250 000 to 500 000 deaths annually. Most deaths associated with seasonal influenza in industrialized countries occur among people age 65 or older.
In 2009, a new strain of influenza, H1N1, entered the global scene. Within the year it had spread to 207 countries, infected 600 000 people, and killed 8000 worldwide. The pandemic alert was raised and a coordinated, concerted effort around the world was implemented to bring this flu under control. H1N1 is most likely a variation of the Spanish flu (also called H1N1) ; this flu was responsible for over 40 million deaths worldwide in the pandemic of 1918 (killing over 2.5% of the entire human population in one year) .
-With H1N1, most deaths occurred under the age of 65. Why might this have been the case?

A) Seniors tend to stay at home so are not in contact with the disease.
B) Seniors, in general, are more resistant to viral infection.
C) Seniors may have had exposure to earlier H1N1 viruses and are thus more immune.
D) This virus targeted the young and healthy.
E) There is no possible explanation.