## **Core Concept**
The question tests knowledge of the innate immune system, specifically the antimicrobial substances present in tears. The correct answer involves an enzyme that breaks down bacterial cell wall components.

## **Why the Correct Answer is Right**
The correct answer, **Lysozyme**, is an enzyme found in tears, saliva, and other bodily secretions that has antimicrobial properties. It works by hydrolyzing the **peptidoglycan** layer of bacterial cell walls, ultimately leading to the destruction of the bacteria. This mechanism is crucial for the innate immune response, providing immediate defense against infections.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not specify a known antimicrobial substance.
- **Option B:** This option is incorrect as it is not recognized as an antimicrobial agent in tears.
- **Option C:** This option is incorrect because, although it might sound related, it does not accurately describe lysozyme or another established antimicrobial substance in tears.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that lysozyme is just one part of the eye's defense mechanism against infection. The eye's surface is also protected by a mucosal barrier and an antimicrobial peptide called **defensin**. Understanding the role of lysozyme and other antimicrobial substances in preventing infection is crucial for ophthalmology and general immunology.

## **Correct Answer:** . **Lysozyme**