Electric current is to be passed from one body to another. For this purpose the two bodies must be joined by

Options

A. cotton thread
B. copper wire
C. plastic string
D. rubber band

Explanation

To solve the question, "Electric current is to be passed from one body to another. For this purpose, the two bodies must be joined by," we need to determine the appropriate material that allows electric current to flow between the two bodies.

### Step-by-Step Solution:

1. **Understanding Electric Current**: Electric current is the flow of electric charge, typically carried by electrons in a conductor.

2. **Identifying Conductors**: To allow electric current to flow from one body to another, we need to use a conductor. Conductors are materials that permit the flow of electric current due to the presence of free electrons.

3. **Analyzing the Options**:
- **Cotton Rod**: This is an insulator and does not allow electric current to flow.
- **Copper Wire**: This is a well-known conductor of electricity and allows current to flow easily.
- **Plastic Ring**: This is also an insulator and does not conduct electricity.
- **Rubber Band**: This is another insulator and does not allow electric current to flow.

4. **Conclusion**: Among the given options, the only material that can effectively conduct electricity and allow electric current to pass from one body to another is the **copper wire**.

### Final Answer:
The two bodies must be joined by **copper wire**.

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