Multidrug-Resistant Tuberculosis means resistance to the drugs:

Correct option is D

Multidrug-Resistant Tuberculosis (MDR-TB) is defined as tuberculosis that is resistant to at least isoniazid and rifampicin, the two most powerful first-line anti-TB drugs. MDR-TB requires longer and more complex treatment with second-line drugs, which are less effective, more toxic, and more expensive.
Explanation of options: (a) Rifampicin and Streptomycin – Streptomycin is not included in the definition of MDR-TB; it’s a second-line injectable agent. (b) Rifampicin and Pyrazinamide – Pyrazinamide resistance alone does not define MDR-TB. Though both are used in treatment, resistance to isoniazid and rifampicin is the key criteria. (c) Isoniazid and Pyrazinamide – While isoniazid resistance is common, rifampicin resistance is essential to define MDR-TB. (d) Isoniazid and Rifampicin – ✔️ This is the correct answer and the WHO-defined criteria for MDR-TB.