<prompt> Follow ing is are the causes of chronic cough with noncontributory chest radiograph-AsthmaPost nasal dripGERDAll the above  <response>: Ans. is d i.e., All the above o 90 of patients who have chronic cough and a normal or noncontributory chest radiograph belong to one of the following causes:Use of an angiotensin-converting enzyme inhibitor;Post-nasal drainage;Gastroesophageal reflux; andAsthma. 