Which of the following is an occupational respiratory disorder?

Silicosis is an occupational respiratory disorder. In certain industries, especially those involving grinding or stone-breaking, so much dust is produced that the defense mechanism of the body cannot fully cope with the situation. Long exposure can give rise to inflammation leading to fibrosis (proliferation of fibrous tissues) and thus causing serious lung damage. Workers in such industries should wear protective masks.

Anthrax is a serious infectious disease caused by gram-positive, rod-shaped bacteria known as Bacillus anthracis. 

Anthracosis  is  caused by the accumulation of carbon particles in the lungs. 

Botulism is a rare and potentially fatal illness caused by a toxin produced by the bacterium Clostridium botulinum.

Emphysema is a chronic disorder in which alveolar walls are damaged due to which respiratory surface is decreased. One of the major causes of this is cigarette smoking.