The solution in which the light is not scattered by the particles is:

Options

A. Suspension
B. Colloidal solution
C. True solution
D. None of these

Answer

To determine the solution in which light is not scattered by the particles, we need to analyze the different types of solutions based on the size of their particles and their interaction with light.

### Step-by-Step Solution:

1. **Identify the Types of Solutions**:
- **Suspension**: Contains larger particles (greater than 1000 nm).
- **Colloidal Solution**: Contains intermediate-sized particles (between 1 nm and 1000 nm).
- **True Solution**: Contains very small particles or solutes (less than 1 nm).
- **None of these**: This option suggests that none of the above solutions fit the criteria.

2. **Understand Light Scattering**:
- Light scattering occurs when the size of the particles is comparable to or larger than the wavelength of light.
- The visible light spectrum typically ranges from about 400 nm to 700 nm.

3. **Analyze Each Solution**:
- **Suspension**: Since the particles are larger than 1000 nm, they will scatter light effectively.
- **Colloidal Solution**: The particles are between 1 nm and 1000 nm, which means they can also scatter light, though not as effectively as suspensions.
- **True Solution**: The particles are less than 1 nm, which is much smaller than the wavelength of visible light. Therefore, they do not scatter light.

4. **Conclusion**:
- Since only the true solution has particles that are too small to scatter light, the answer to the question is that the solution in which light is not scattered by the particles is a **True Solution**.

### Final Answer:
The solution in which the light is not scattered by the particles is: **True Solution**.