Correct Answer:
B. All over Punjab
The geographical area of enforcement for this Act is All over Punjab (B). This is inferred from the fact that the 'Government of Punjab' is responsible for updating the list of essential goods, indicating it is a provincial law. Provincial laws typically apply throughout the entire province, not just 'Lahore only' (A) or 'Selected districts' (D). It is not a federal law, so 'Whole Pakistan' (C) is incorrect.