11. Salmeterol, Ipratropium, and Albuterol are three of the common drugs prescribed to those with obstructive pulmonary disease. All of these drugs dilate the bronchus. In the airway, acetylcholine triggers contraction of smooth muscle; and ipratropium hinders the binding of acetylcholine. Salmeterol has the longest effect of the three drugs because of its lipophilic character. It directly causes relaxation of the muscle in a patient’s airway. Albuterol is a short-acting drug due to its hydrophilic character; it also directly causes the smooth muscles to relax. Both Albuterol & Salmeterol bind to 2-adenergic receptors, which have a high affinity for Adrenaline. A larger dose of salmeterol is required to cause the same effect to that of albuterol or adrenaline. Using the information above, indicate how each of the drug behaves (agonist or antagonist) and match the structures A-C with the three drugs. Provide an explanation for your reasoning.