Correct Answer: 2 [Prime Minister and former Prime Ministers]

Notes:
The Special Protection Group Act, 1988 was passed by the parliament after the assassination of former Prime Minister Indira Gandhi.
It aimed to provide for regulation of an armed force of the Union for providing security to the Prime Minister of India and the former Prime Ministers of India and members of their immediate families. It was extended to all former Prime Ministers and their immediate families after former Prime Minister Rajiv Gandhi was assassinated.