Some suspensions are given
1. Fog
2. Air
3. Blood
4. Paint
5. Aerosol spray
Among the following, true suspensions are

Options

A. A. 1,2 and 3
B. B. 3,4 and 5
C. C. 1,3 and 5
D. D. 1,3 and 4

Explanation

To determine which of the given options are true suspensions, we first need to understand the definition of a true suspension.

### Step-by-Step Solution:

1. **Understand the Definition of True Suspension**:
- A true suspension is a heterogeneous mixture where small solid particles are dispersed throughout a liquid but do not dissolve in it. These particles remain suspended in the liquid.

2. **Analyze Each Option**:
- **Fog**: Fog is a mixture of tiny water droplets suspended in air. It can be considered a true suspension because the water droplets do not dissolve in the air.
- **Air**: Air is a homogeneous mixture of gases and does not contain solid particles suspended in a liquid. Therefore, it is not a true suspension.
- **Blood**: Blood is a complex fluid that contains cells (red blood cells, white blood cells, platelets) suspended in plasma. It qualifies as a true suspension because the cells do not dissolve in the plasma.
- **Paint**: Paint is a colloidal mixture where pigments are suspended in a liquid medium. It is not classified as a true suspension but rather as a colloid.
- **Aerosol Spray**: Aerosols consist of tiny liquid droplets or solid particles suspended in a gas. Similar to paint, it is also classified as a colloid, not a true suspension.

3. **Identify True Suspensions**:
- Based on the analysis, the true suspensions from the options provided are:
- Fog
- Blood

4. **Conclusion**:
- The correct answer is that the true suspensions among the options are Fog and Blood.

### Final Answer:
- True suspensions are: **Fog and Blood**.