Which fuel does not burn with a flame? Comment.

Explanation

### Step-by-Step Solution:

1. **Understanding Fuel and Flame**:
- A fuel is a substance that can be burned to produce energy. When a fuel burns, it usually produces a flame.

2. **Vaporization and Flame Production**:
- For a fuel to produce a flame, it needs to vaporize when heated. Vaporization is the process where a solid or liquid turns into vapor (gas) when heated.

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