The correct option is "2 only" because, while the Leader of the Opposition was officially recognized in the Lok Sabha in 1969, the first Lok Sabha (1952-1957) did not have this designation; it was a convention rather than a formal title. The Swatantra Party was indeed a significant party in the 1960s but was not the single largest party in opposition in the first Lok Sabha. Additionally, the criterion for recognition as the Leader of the Opposition requires a party to have a minimum of 10% of the total membership, which is 55 members in the current Lok Sabha, not 75. This reflects the importance of formal structures and norms within India's parliamentary democracy, which is crucial for understanding the functioning and evolution of political roles in governance as covered in standard UPSC resources.