Pyrolysis is

Options

A. Biochemical process
B. Biological Process
C. Thermochemical process
D. Petrochemical process

Answer

### Step-by-Step Solution

1. **Understanding Pyrolysis**:
- Pyrolysis is a process that involves the thermal decomposition of materials at elevated temperatures in an inert atmosphere. This means it occurs in the absence of oxygen.

2. **Analyzing the Options**:
- The question provides four options:
1. Biochemical process
2. Biological process
3. Thermochemical process
4. Petrochemical process

3. **Evaluating Each Option**:
- **Biochemical Process**:
- This involves chemical reactions facilitated by living organisms. Since pyrolysis does not involve living organisms, this option is incorrect.
- **Biological Process**:
- Similar to the biochemical process, this involves reactions vital for the survival of living organisms. Pyrolysis does not fit this definition, making this option incorrect as well.
- **Thermochemical Process**:
- This involves chemical reactions that result in a change of state due to temperature changes. Pyrolysis fits this definition as it involves the decomposition of materials due to high heat. Therefore, this option is correct.
- **Petrochemical Process**:
- This refers to the conversion of natural gas or oil into chemical products. While pyrolysis can be related to petrochemicals, it is primarily characterized as a thermochemical process.

4. **Conclusion**:
- Based on the analysis, the correct answer is that pyrolysis is a **thermochemical process**.

### Final Answer:
**Pyrolysis is a thermochemical process.**