The S.I. unit of electric dipole moment is:

Options

A. `C-m^2`
B. C-m
C. C/m
D. `C//m^2`

Explanation

To determine the S.I. unit of electric dipole moment, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Electric Dipole**:
- An electric dipole consists of two equal and opposite charges separated by a distance. For example, if we have a positive charge \( +Q \) and a negative charge \( -Q \), separated by a distance \( R \), this system is an electric dipole.

2. **Define Electric Dipole Moment**:
- The electric dipole moment \( \vec{p} \) is defined as the product of the magnitude of one of the charges and the distance between the charges. Mathematically, it is expressed as:
\[ \vec{p} = Q \cdot R \]
- Here, \( Q \) is the magnitude of the charge and \( R \) is the separation distance between the charges.

3. **Identify the S.I. Units**:
- The S.I. unit of charge \( Q \) is the Coulomb (C).
- The S.I. unit of distance \( R \) is the meter (m).

4. **Combine the Units**:
- Therefore, the S.I. unit of electric dipole moment can be derived as follows:
\[ \text{S.I. unit of electric dipole moment} = \text{Coulomb} \times \text{meter} = \text{C} \cdot \text{m} \]

5. **Conclusion**:
- The S.I. unit of electric dipole moment is Coulomb meter (C·m).

### Final Answer:
The S.I. unit of electric dipole moment is **Coulomb meter (C·m)**.