Explanation:

- Alien Enemy: A person who is not a citizen of India and belongs to a country that is at war with India.

- Alien Friend: A person who is not a citizen of India but belongs to a country that is not at war with India.

- Either (a) or (b): This option acknowledges that a non-Indian citizen can be classified as either an alien enemy or an alien friend based on their country's relationship with India.

- Both (a) and (b): This implies simultaneous classification as both an enemy and a friend, which is not logically possible.

Correct Answer: Option:3 - Either (a) or (b)