Which of the following gas is used in Gas-lighter?

Options

A. Butane
B. Propane
C. Radon
D. Methane

Explanation

**Step-by-Step Solution:**

1. **Identify the Options**: The question asks which gas is used in gas lighters. Typically, gas lighters use a specific type of gas for ignition.

2. **Consider Common Gases Used in Lighters**: The most common gases used in gas lighters are butane and propane. Both are hydrocarbons and are part of the liquefied petroleum gas (LPG) family.

3. **Recall the Chemical Formula**: Butane has the chemical formula C4H10. This is an important detail because it distinguishes butane from other gases.

4. **Eliminate Other Options**:
- Propane (C3H8) is also used in some lighters but is less common than butane in standard disposable lighters.
- Methane (CH4) is primarily used in natural gas and is not typically found in gas lighters.
- Radon is an inert gas and does not serve as a fuel source.

5. **Conclude with the Correct Answer**: Based on the information, the gas that is primarily used in gas lighters is butane.

**Final Answer**: Butane (C4H10) is the gas used in gas lighters.

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