This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
MDR tuberculosis is defined by : 
Select and explain. 
A. Resistance to all first and second line anti-tubercular agents, B. Resistance to any three first line anti-tubercular agents, C. Resistance to all first line and any three classes of second line anti-tubercular agents, D. Resistance to isoniazid and rifampicin
D: Resistance to isoniazid and rifampicin
Answer: D: Resistance to isoniazid and rifampicin 
Explanation: None