Which one of the following Articles of the Constitution of India says that the executive power of every State shall be so exercised as not to impede or prejudice the exercise of the executive power of the Union?

1. The question asks which Article of the Constitution of India mandates that the executive power of a State should be exercised without impeding or prejudicing the executive power of the Union. 2. Article 257(1) states: "The executive power of every State shall be so exercised as not to impede or prejudice the exercise of the executive power of the Union, and the executive power of the Union shall extend to the giving of such directions to a State as may appear to the Government of India to be necessary for that purpose." This directly matches the requirement. 3. Article 258 deals with the power of the Union to confer powers, etc., on States in certain cases. 4. Article 355 deals with the duty of the Union to protect States against external aggression and internal disturbance. 5. Article 356 deals with provisions in case of failure of constitutional machinery in States (President's Rule). Therefore, Article 257 contains the specified provision.