This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
A 50-year male quaz quarry worker presents with progressive dyspnoea on exeion. Which of the following is the likely pneumoconiosis? 
Select and explain. 
A. Asbestosis, B. Byssinosis, C. silicosis, D. Berylliosis
C: silicosis
Answer: C: silicosis 
Explanation: The major occupational exposures of free silica(SiO2)or crystalline quaz,include mining,stonecutting,employment in abrasive industries such as stone,clay,glass & cement manufacturing,foundry work,packing of silica flour,and quarrying paicularly of granite. Asbestosis is caused by exposure to asbestos-mining,processing,construction,ship repair.Berylliosis is caused by exposure to beryllium-processing alloys for high-tech industries.Exposure to organic dusts like cotton dust-milling,processing can produce byssinosis,which is an asthma-like syndrome. Ref:Harrison's medicine-18th edition,page no:2123