A 61 year old plumber was diagnosed with chronic obstructive pulmonary disease in 2020. He was a chronic smoker

A 61 year old plumber was diagnosed with chronic obstructive pulmonary disease in 2020. He was a chronic smoker for 40 years and smokes 20 cigarettes a day. He has been experiencing increased dyspnea at rest for four days. Dyspnea began after an upper respiratory tract infection a month ago. He also reported wheezing and a cough with mucoid sputum. He denies chest pain or palpitations. He reported that he was compliant with his treatment plan and had no recent medication changes. He also has hypertension, hyperlipidemia, and type 2 diabetes. He denies alcohol or drug misuse. He has no known drug, medication or latex allergies. Current medications include Metoprolol 10mg PO daily, Atorvastatin 20mg PO daily (last dose 8 PM yesterday for his hyperlipidemia) and Meformin 850mg BID for DM. Denies any ASA use but takes Tylenol or ibuprofen when he has a headache. He claims headaches are not frequent. He saw his PCP every 6 months and had a normal EKG and stress test 3 months ago. Give 3 possible differential diagnoses and explain why each was ruled out. The plan for this patient, education provided and the lab test need to confirm the the presumptive diagnosis