Consider the following statements An iron cored choke is non linear and passive device. A carbon resistor kept in sunlight is a time invariant and passive device. A dry cell is a time varying and active device. An air capacitor is time invariant and passive device. Of these statements

• 1, 2, 3 and 4 are correct
• 1, 2, 3 are correct
• 1, 2, 4 are correct
• 2 and 4 are correct