This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mycobacterial Infections, Subject name: Dental
In leprosy neural involvement occurs in what percentage of patients 
Select and explain. 
A. 30%, B. 60%, C. 90%, D. 100%
D: 100%
Answer: D: 100% 
Explanation: A chronic granulomatous disease caused by Mycobacterium leprae, principally affecting peripheral nerves and skin. Nerve involvement is seen in all cases of leprosy. The cardinal signs are: 1. Hypopigmented/hypoanaesthetic patches 2. Peripheral nerve thickening 3. Skin slit smear(AFB).