Ohm's Law is not applicable when the temperature is:

Explanation

Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage across it, provided the temperature and other physical conditions remain constant. When the temperature changes, it can affect the resistance of the material, making Ohm's Law not applicable. This is why the correct answer is 'Changing'. A constant temperature ensures resistance remains unchanged, validating Ohm's Law, which makes 'Constant' an incorrect option. 'All of These' is incorrect because Ohm's Law is applicable when temperature is constant. 'None of these' is incorrect because a changing temperature is a specific condition that affects the applicability of Ohm's Law.