What metal is used to make ferronmagnets?

Options

A. iron
B. cobalt
C. nickel
D. all of the above

Explanation

**Step-by-Step Solution:**

1. **Understanding Ferromagnets**:
- Ferromagnets are materials that can be magnetized and are strongly attracted to magnets. They have a high magnetic permeability and retain their magnetic properties even after the external magnetic field is removed.

2. **Identifying the Metals Used**:
- The metals commonly used to make ferromagnets include:
- **Iron**: This is the most widely used metal for ferromagnets due to its strong magnetic properties.
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