The refining or purification of metals by passing electric current is called :

Options

A. electroplating
B. electrolysis
C. electrorefining
D. none of these

Answer

To solve the question, we need to identify the correct term that describes the process of refining or purifying metals by passing electric current. Let's analyze the options given:

1. **Electroplating**: This process involves coating one metal with another using electric current. It is primarily used for decorative purposes or to prevent corrosion, not specifically for purification.

2. **Electrolysis**: This is a broader term that refers to the process where ionic substances break down into simpler substances when an electric current is passed through them. While it is related to the process of electrorefining, it does not specifically refer to the purification of metals.

3. **Electrorefining**: This term specifically refers to the purification of metals by passing electric current through a solution containing the metal ions. In this process, impurities are removed, and pure metal is deposited at the cathode.

4. **None**: This option would imply that none of the terms fit the description, which is not the case here.

Based on the definitions and the context of the question, the correct answer is:

**Electrorefining**.

### Step-by-Step Solution:
1. **Identify the process**: We are looking for a process that involves the purification of metals using electric current.

2. **Analyze the options**:
- Electroplating: Coating of one metal with another.
- Electrolysis: Breakdown of ionic substances, not specifically for purification.
- Electrorefining: Purification of metals using electric current.
- None: Not applicable since we have a valid term.

3. **Select the correct term**: Among the options, "Electrorefining" is the term that specifically refers to the purification of metals by passing electric current.

4. **Conclude the answer**: Therefore, the refining or purification of metals by passing electric current is called **Electrorefining**.