Two People Are Allergic to Ragweed, but Bill of Them

Two people are allergic to ragweed, but Bill of them has mild symptoms in his nose and eyes whereas the Sue experiences severe asthma. There are 17 species of ragweed. What are possible reasons for the difference in their symptoms?

A) The pollen that Sue, the person with asthma is allergic to may be smaller in molecular weight and thus go more deeply into her lungs and in addition Sue may have more IgE to the allergen than Bill.
B) The pollen that Sue, the person with asthma is allergic to may be larger in molecular weight and thus go more deeply into ther lungs and in addition she may have more IgE to the allergen.
C) The pollen that Bill, person with mild symptom is allergic to may be larger in molecular weight and thus go more deeply into his lungs and he may have more IgE to the allergenso the reaction occurs as soon as the allergen enters.
D) The pollen that Bill, the person with mild symptom is allergic to may be smaller and thus go more deeply into his lungs and and he may have more IgE to the allergen and thus he would experience the reaction as soon as the allergen enters.