Explanation:

- Option 1: 44 years

- This is the correct answer.

- On the eve of India's Independence in 1947, the life expectancy at birth was approximately 44 years.

- The country faced numerous health challenges and limited medical facilities.

- Option 2: 50 years

- This was not the life expectancy at the time of independence.

- Improvement in healthcare systems led to this figure in later decades.

- Option 3: 60 years

- This level of life expectancy was achieved much later.

- It reflects more recent advances in healthcare and living conditions.

- Option 4: All of these

- Not applicable because only one option is correct.