Fire extinguisher is used to:

Options

A. cut off the supply of air
B. bring down the temperature of fuel
C. both(A) and (B)
D. none of the above

Explanation

**Step-by-Step Solution:**

1. **Understanding the Purpose of a Fire Extinguisher:**
- A fire extinguisher is a device used to put out or control small fires. It works by removing one or more elements of the fire triangle: heat, fuel, and oxygen.

2. **Cutting Off the Supply of Air:**
- One of the primary functions of a fire extinguisher is to cut off the supply of air (oxygen) to the fire. Fire requires oxygen to sustain combustion. By reducing the amount of oxygen available, the fire cannot continue to burn effectively.

3. **Bringing Down the Temperature of the Fuel:**
- Another function of a fire extinguisher is to lower the temperature of the burning material (fuel). Every fuel has a minimum temperature at which it ignites and burns. By cooling the fuel, the fire extinguisher can prevent the fire from continuing to burn.

4. **Evaluating the Options:**
- Option 1: Cutting off the supply of air - Correct.
- Option 2: Bringing down the temperature of the fuel - Correct.
- Option 3: Both A and B - Correct.

5. **Conclusion:**
- Since both options 1 and 2 are correct, option 3, which states "Both A and B," is also correct. Therefore, the fire extinguisher serves both purposes: cutting off the air supply and reducing the temperature of the fuel.

**Final Answer:**
Fire extinguishers are used to cut off the supply of air and bring down the temperature of the fuel, making option 3 (Both A and B) the correct choice.

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