**Core Concept**
Sputum examination under Directly Observed Treatment Short-Course (DOTS) is a crucial diagnostic tool for tuberculosis (TB) control, especially in high-burden settings. It helps in identifying TB cases and monitoring treatment adherence.

**Why the Correct Answer is Right**
Hemoptysis, or coughing up blood, is a significant symptom that warrants immediate investigation, including sputum examination under DOTS. This is because hemoptysis can be indicative of active TB, especially in patients with a prolonged history of cough. The presence of blood in sputum is a red flag for TB, and prompt sputum examination can lead to early diagnosis and treatment initiation. The DOTS program emphasizes early detection and treatment of TB cases to prevent transmission and disease progression.

**Why Each Wrong Option is Incorrect**
**Option A:** A cough of 1-2 weeks duration is not considered a definitive indicator for TB, and sputum examination under DOTS is not typically recommended at this stage.

**Option B:** Persistent cough of 1-2 weeks duration may be suggestive of TB or other respiratory infections, but it is not a strong enough indicator for sputum examination under DOTS.

**Option D:** Chest pain is a nonspecific symptom that can be associated with various conditions, including TB, but it is not a reliable indicator for sputum examination under DOTS.

**Clinical Pearl / High-Yield Fact**
For patients presenting with hemoptysis, it is essential to consider TB in the differential diagnosis, especially in areas with high TB prevalence. Early sputum examination under DOTS can lead to timely diagnosis and treatment, reducing the risk of TB transmission and disease spread.

**✓ Correct Answer: C. Hemoptysis**