It the following processes, identify the irreversible process `:`

Options

A.
B.
C.
D.

Explanation

To identify the irreversible process among the given options, we need to understand the characteristics of reversible and irreversible processes in thermodynamics.

### Step-by-Step Solution:

1. **Understanding Reversible Processes**:
- A reversible process is one where the system remains in equilibrium throughout the process. This means that any change in pressure and volume occurs in a smooth and continuous manner, without any sudden jumps or breaks.
- Graphically, the pressure-volume (P-V) curve for a reversible process is regular and can be either linear or curved, but it does not have any abrupt changes.

2. **Understanding Irreversible Processes**:
- An irreversible process is characterized by sudden changes in pressure or volume, meaning that the system does not remain in equilibrium during the process.
- In a P-V graph, this would appear as a sudden drop or spike in pressure or volume, indicating that the system has undergone a change that is not gradual.

3. **Analyzing the Given Options**:
- For each option provided, we need to check the nature of the P-V graph:
- **Option 1**: Regular change in pressure and volume (Reversible)
- **Option 2**: Regular change in pressure and volume (Reversible)
- **Option 3**: Regular change in pressure and volume (Reversible)
- **Option 4**: Sudden change in pressure or volume (Irreversible)

4. **Identifying the Irreversible Process**:
- After analyzing the options, we find that **Option 4** shows a sudden change in either pressure or volume, indicating that the system is not at equilibrium during this process. Therefore, this option represents an irreversible process.

5. **Conclusion**:
- The irreversible process among the given options is **Option 4**.