Consider the following statements about mutual inductances:1. The value should remain constant under all conditions.2. The mutual inductance should not vary with temperature.3. The inductance should be independent of excitation.4. They have two coils wound on a bobbin of hard magnetic material, coils being separated by a range. Out of the above, correct statement are

• A. 2, 3, 4
• B. 1, 2, 3
• C. 1, 3, 4
• D. 1, 2, 4