The answer to the question is possibly A
Ragweed antigens bind ragweed and then bind mast cells which release histamine
<span>Allergies develop because of a Th2 response against the allergen. </span>
-3x + 3(2x - 6) = 6
-3x +6x - 18 = 6
3x - 18 = 6
3x = 6 + 18
3x = 24
x = 8
hope this helped, blessing! :)