_________ is good conductor of electricity.

Options

A. Metal
B. Rubber
C. Plastic
D. All of these

Answer

To solve the question "_________ is a good conductor of electricity," we need to analyze the options provided: metal, rubber, plastic, and all of these.

### Step-by-Step Solution:

1. **Understanding Conductors**: First, we need to understand what a conductor is. A conductor is a material that allows electricity to flow through it easily.

2. **Identifying the Options**:
- **Metal**: Metals are known for their ability to conduct electricity. They have free electrons that facilitate the flow of electric current.
- **Rubber**: Rubber is an insulator, which means it does not conduct electricity well. It is used to prevent the flow of electricity.
- **Plastic**: Like rubber, plastic is also an insulator and does not conduct electricity effectively.
- **All of these**: This option suggests that all the materials listed (metal, rubber, plastic) are good conductors, which is incorrect based on our analysis.

3. **Analyzing the Best Option**: Since metals are known to be good conductors of electricity, while rubber and plastic are not, the best option that fits the statement is "metal."

4. **Conclusion**: Therefore, the correct answer to the question is "metal."

### Final Answer:
**Metal** is a good conductor of electricity.

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