Two colleagues that share the same office are exposed to the flu virus one week in January. Janet just recovered from the same flu virus two weeks earlier, while Mark has not been sick yet this winter. Which person do you expect would be more likely to become sick with this flu virus and why? a
Janet: since she already had the flu, her immune system is weaker than Mark's.

b
Janet: she will most likely get the flu again, and a more severe case of it.

c
Mark: he has not acquired any active immunity to the flu, and Janet has.

d
Mark: he has only passive immunity to the flu which will not benefit him in this case.