Explanation:

- In 1978, the Janata Party government announced the formation of the second backward classes commission.

- This commission was led by B.P. Mandal and is often referred to as the Mandal Commission.

- The purpose of the commission was to identify socially or educationally backward classes in India and make recommendations for their advancement.

- Option 1: The Indian National Congress Party was not in power in 1978. They were defeated in the 1977 elections.

- Option 2: Bharatiya Janata Party did not exist as a separate entity in 1978. It was formed later in 1980.

- Option 3: The Janata Party was the ruling party after the 1977 elections and responsible for the commission's formation.

- Correct Answer: Option 3 - Janata Party

- Option 4: United Democratic Party is not relevant to this context.