Paste is

Options

A. Suspension of solid in a liquid
B. Mechanical dispersion of a solid in liquid
C. Colloidal solution of a solid in solid
D. None of these

Explanation

To answer the question "Paste is," we need to analyze the options provided and understand the nature of a paste.

### Step-by-Step Solution:

1. **Understanding the Definition of Paste**:
- A paste is a thick, soft, moist substance typically made by mixing a solid with a liquid. The solid particles are often larger than those found in a colloid.

2. **Analyzing the Options**:
- **Option 1: Suspension of solid and liquid**: This suggests that solid particles are dispersed in a liquid medium. This is a common characteristic of pastes.
- **Option 2: Mechanical dispersion of solid and liquid**: This implies a physical mixing process, which may not accurately describe the nature of a paste.
- **Option 3: A large solution of solid and solid**: This suggests a mixture of solids, which does not accurately describe a paste.
- **Option 4: None of these**: This would imply that none of the previous definitions apply, which we will evaluate after considering the first three options.

3. **Identifying the Correct Option**:
- Given that a paste consists of solid particles suspended in a liquid, the most accurate description is **Option 1: Suspension of solid and liquid**. This is because the solid particles are not dissolved but rather suspended in the liquid, which is characteristic of a paste.

4. **Conclusion**:
- Therefore, the correct answer to the question "Paste is" is **Option 1: Suspension of solid and liquid**.