The desirable properties of core of a transformer are

The correct answer is Option (3) → High permeability and low hysteresis loss

Explanation:

The core of a transformer should have high permeability so that magnetic flux can pass easily through it, reducing magnetizing current. It should also have low hysteresis loss to minimize energy loss during each cycle of magnetization and demagnetization.

Hence, the correct option is High permeability and low hysteresis loss.