Types of fuel on the basis of source are

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the types of fuel based on their source.

2. **Classification of Fuels**: Fuels can be classified into two main types based on their source:
- **Primary Fuels**
- **Secondary Fuels**

3. **Defining Primary Fuels**:
- Primary fuels are those that are found in nature and can be extracted, cleaned, or graded without any energy conversion or transformation processes.
- **Examples of Primary Fuels**:
- Coal
- Crude Oil

4. **Defining Secondary Fuels**:
- Secondary fuels are derived from primary fuels through physical and chemical processes.
- **Examples of Secondary Fuels**:
- Kerosene
- Methane

5. **Summary**:
- In summary, fuels can be categorized into primary fuels, which are directly obtained from nature, and secondary fuels, which are processed from primary fuels.