## Core Concept
The resolution of a microscope is its ability to distinguish between two closely spaced points as separate entities. It is a measure of the microscope's ability to produce clear, detailed images. The resolution of a light microscope is limited by the wavelength of light.

## Why the Correct Answer is Right
The resolution of a light microscope is given by the formula: $R = frac{0.61 lambda}{NA}$, where $R$ is the resolution, $lambda$ is the wavelength of light, and $NA$ is the numerical aperture of the objective lens. The wavelength of visible light ranges from approximately 400 to 700 nanometers. Using this formula and considering the average wavelength of visible light, the resolution of a light microscope is approximately **0.2 microns (μm)** or **200 nanometers (nm)**.

## Why Each Wrong Option is Incorrect
* **Option A:** This option is incorrect because the value provided does not match the known resolution limit of a light microscope.
* **Option B:** This option is incorrect for the same reason as option A; it does not accurately represent the resolution of a light microscope.
* **Option D:** This option suggests a much larger value than what is known for the resolution of a light microscope, making it incorrect.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the resolution of a light microscope is approximately **0.2 μm**, which limits its ability to distinguish between very small structures such as viruses or detailed structures within cells. This limitation is why electron microscopes, which have a much higher resolution, are used for studying such tiny entities.

## Correct Answer Line
**Correct Answer: C. 0.2 μm.**