57. A patient presents with breathlessness and occasional dry cough. On physical examination, he is found to have bilateral basal crepitations. His pulmonary function tests reveal a decrease in total lung capacity and vital capacity(VC), with normal FEV1/FVC ratio. He is most likely suffering from:
(a) Chronic bronchitis
(b) Idiopathic pulmonary fibrosis
(c) Cystic fibrosis
(d) Allergic bronchopulmonary aspergillosis