**Core Concept**
Disinfection of sputum involves eliminating pathogenic microorganisms while preserving the integrity of the specimen for laboratory analysis. Effective disinfection methods must balance microbial killing with minimal damage to the specimen.

**Why the Correct Answer is Right**
Autoclaving is the preferred method for disinfecting sputum due to its high efficacy and ability to kill a wide range of microorganisms, including bacteria, viruses, and fungi. Autoclaving involves subjecting the sputum to high-pressure steam at 121°C for 15-20 minutes, which denatures proteins, disrupts cell membranes, and ultimately leads to microbial death.

**Why Each Wrong Option is Incorrect**
**Option A:** Boiling is not sufficient for disinfecting sputum as it may not reach the required temperature to kill all microorganisms and can cause degradation of the specimen.
**Option C:** Sunlight lacks sufficient intensity and duration to effectively disinfect sputum, and its efficacy can be reduced by factors such as cloud cover and distance from the sun.
**Option D:** Burning is not a suitable method for disinfecting sputum as it can cause charring and destruction of the specimen, making it unusable for laboratory analysis.
**Option E:** Airing is not effective for disinfecting sputum as it relies on passive diffusion and may not remove all microorganisms, especially those that are resistant to desiccation.

**Clinical Pearl / High-Yield Fact**
When handling sputum specimens, it's essential to follow proper disinfection and handling procedures to prevent cross-contamination and ensure accurate laboratory results.

**Correct Answer: B. Autoclaving**