**Core Concept**
Disinfection of sputum is a critical step in microbiology laboratories to eliminate pathogenic microorganisms, particularly Mycobacterium tuberculosis, from clinical specimens. Effective disinfection methods must be able to inactivate these resistant organisms.

**Why the Correct Answer is Right**
Autoclaving is a reliable method for disinfecting sputum samples. This process involves subjecting the sample to high-pressure steam at 121°C for 15-20 minutes, which is sufficient to kill Mycobacterium tuberculosis. Autoclaving works by denaturing proteins, disrupting cell membranes, and ultimately causing the death of the microorganisms.

**Why Each Wrong Option is Incorrect**
* **Option A:** Boiling is not sufficient for disinfecting sputum, as it may not reach the temperatures required to kill Mycobacterium tuberculosis.
* **Option C:** Sunlight, while useful for disinfecting surfaces, is not effective against the spores of Mycobacterium tuberculosis.
* **Option D:** Burning is a physical method of destruction, but it may not be practical or safe for laboratory settings.
* **Option E:** Airing, or simply allowing the sputum sample to sit at room temperature, is not a reliable method for disinfection, as microorganisms may still be viable.

**Clinical Pearl / High-Yield Fact**
When handling sputum samples, it's essential to use personal protective equipment (PPE) and follow strict laboratory protocols to prevent exposure to potential pathogens.

**Correct Answer: B. Autoclaving**