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: Anatomy
Which of the following is true about pneumoconiosis 
Select and explain. 
A. Pleural plaques of asbestosis is always symptomatic, B. Silicosis is not associated with increased risk of tuberculosis, C. Asbestosis and smoking act synergistically to cause lung cancer, D. Coal workers pneumoconiosis is associated with lung cancer
C: Asbestosis and smoking act synergistically to cause lung cancer
Answer: C: Asbestosis and smoking act synergistically to cause lung cancer 
Explanation: Lung cancer is the most common cancer associated with asbestos exposure. The excess frequency of lung cancer (all histologic types) in asbestos workers is associated with a minimum latency of 15-19 years between first exposure and development of the disease. Persons with more exposure are at greater risk of disease. In addition, there is a significant interactive effect of smoking and asbestos exposure that results in greater risk than what would be expected from the additive effect of each factor. Ref Harrison 19th edition pg 1687-88