You and Your Friend Were Equally Exposed to a Virus

You and your friend were equally exposed to a virus, but over the next few days, only your friend acquired flu-like symptoms and was ill for almost a week before recovering. Which one of the following is a logical explanation for this?

A) Your inflammatory response worked more quickly than your friend's response.
B) You had an immunological memory of that virus.
C) Your friend had an autoimmune disorder.
D) Your friend had allergies.