**Core Concept**
The management of tuberculosis (TB) involves the use of **antitubercular drugs** to target the causative organism, *Mycobacterium tuberculosis*. The goal is to prevent the development of **drug resistance** and ensure effective treatment.

**Why the Correct Answer is Right**
A patient with newly diagnosed pulmonary TB, especially if they have a positive **sputum smear** for acid-fast bacilli, requires **multidrug therapy** to cover the possibility of **drug-resistant strains**. This approach typically involves a combination of **isoniazid**, **rifampicin**, **pyrazinamide**, and **ethambutol**.

**Why Each Wrong Option is Incorrect**
**Option A:** Not enough information is provided to determine if this patient requires multidrug therapy.
**Option B:** Similarly, this option lacks specific details about the patient's condition.
**Option C:** Without knowing the patient's diagnosis or treatment history, it's impossible to decide on the appropriate therapy.
**Option D:** This option is also unclear regarding the necessity for multidrug therapy.

**Clinical Pearl / High-Yield Fact**
In TB treatment, using a combination of drugs is crucial to prevent the emergence of **drug-resistant TB**, which is a significant public health concern.

**Correct Answer:** D. A new patient with pulmonary TB.