## Core Concept
The identification of dried semen stains is crucial in forensic science. Semen contains **spermatozoa**, **enzymes**, and other **glycoproteins** that can be detected through various methods. The presence of semen can be confirmed through microscopic examination, biochemical assays, or immunological tests.

## Why the Correct Answer is Right
The correct answer involves the use of **ultraviolet (UV) light** or **fluorescence** to detect semen stains. When exposed to UV light, semen fluoresces due to the presence of **tryptophan** and other **fluorescent compounds**. This property makes UV light a useful tool for preliminary screening of suspected semen stains on clothing or other materials.

## Why Each Wrong Option is Incorrect
* **Option A:** This option is incorrect because, although **microscopic examination** can identify spermatozoa, it's not the most efficient method for detecting dried semen stains on clothes.
* **Option B:** This option is incorrect as it does not accurately represent a common method for detecting semen.
* **Option C:** This option is incorrect because, while **biochemical assays** can detect components of semen, the question seems to point towards a more immediate, visual, or simple detection method.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **forensic examination** of suspected semen stains often begins with **UV light inspection** due to its simplicity and non-destructive nature. This method can guide further forensic analysis.

## Correct Answer Line
**Correct Answer: D. Ultraviolet light**.