A 30-year-old-man is evaluated for on and off exertional dyspnea since he was a teenager. His spirometry pre and post bronchodilator reveals the following: Pre % Predicated pre Post % Predicated post FEV1 2.3 L 68% 2.74 L 81% FVC 3.83 L 91% 3.98 L 94% FEV1: FVC ratio 0.64 85% 0.66 87% What is most likely the diagnosis?