<prompt> Following isare the causes of a chronic cough with noncontributory chest radiograph?AsthmaPost nasal dripGERDAll the above  <response>: 90 of patients who have a chronic cough and a normal or noncontributory chest radiograph belong to one of the following causes:Use of an angiotensin-conveing enzyme inhibitor;Post -nasal drainage;Gastroesophageal reflux; andAsthmaRef: PL Dhingra, Diseases of Ear, Nose Throat, 7th edition 