**Core Concept**
Carnoy's solution is a fixative used in histopathology to preserve tissue samples, preventing autolysis and maintaining cellular structures for microscopic examination. It is a mixture of ethanol, chloroform, and acetic acid.

**Why the Correct Answer is Right**
Carnoy's solution is used to preserve tissue samples, especially in the case of biopsy specimens or autopsy samples. The mixture of ethanol, chloroform, and acetic acid helps to prevent autolysis by denaturing proteins and coagulating cellular enzymes. This allows for better preservation of cellular structures and prevents the degradation of tissue samples.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Carnoy's solution is not used for disinfection.
**Option B:** This option is incorrect because Carnoy's solution is not used as an antiseptic.
**Option C:** This option is incorrect because Carnoy's solution is not used as a skin disinfectant.

**Clinical Pearl / High-Yield Fact**
Carnoy's solution is a fixative that prevents autolysis by denaturing proteins and coagulating cellular enzymes, making it essential in histopathology for preserving tissue samples.

**Correct Answer: C. Tissue preservation.**