Cromolyn sodium

Cromolyn sodium
Cromolyn sodium inhibits the degranulation of mast cells and therefore the release of histamines and leukotrienes. The exact mechanism is
not known. Cromolyn sodium has a short duration of action. So it needs to be applied at least 4 times a day. In hay fever periods the drug can best be used as prophylaxis. But since the maximal prophylactic effect is reached after several weeks dosing should start early. The drug is generally well tolerated.Cromolyn sodium is drug of choice for chronic allergic rhinitis in children.
1

Which one of the following substances works to directly reverse bronchoconstriction and hence is the treatment of choice in severe, allergic respiratory distress? 

2

Which of the following substances could prevent the ragweed allergen from reaching the sensitized mast cell?