<prompt> Following is are the causes of chronic cough with noncontributory chest radiograph?AsthmaPost nasal dripGERDAll the above  <response>: 90 of patients who have chronic cough and a normal or noncontributory chest radiograph belong to one of the following causes:i Use of an angiotensin-conveing enzyme inhibitorii Post-nasal drainageiii Gastroesophageal reflux andiv Asthma. 