Explanation:

- The All-India Harijan Sevak Sangh was indeed founded in 1932.

- It was established by Mahatma Gandhi with the purpose of eradicating untouchability and improving the social status of Harijans (now referred to as Dalits).

- Option 1: 1932 is the correct answer.

- Option 2: 1942, is incorrect. World War II was a prominent event at this time, but the Harijan Sevak Sangh had already been established.

- Option 3: 1928, is also incorrect. Although it was a period of significant social reform in India, the organization was not founded yet.

- Option 4: 1919, precedes the founding by over a decade. This year is too early for the establishment of the Sangh.