The correct answer for this question is option 1, Atmaram Pandurang. The Prarthana Samaj was founded by Atmaram Pandurang during the Indian Freedom Struggle.

Option 2, Gopal Hari Deshmukh, is not the correct answer. Gopal Hari Deshmukh, also known as Lokhitwadi, was a social reformer and journalist, but he did not found the Prarthana Samaj.

Option 3, Ishwar Chandra Vidyasagar, is also not the correct answer. Ishwar Chandra Vidyasagar was a prominent social reformer and educationist in 19th-century Bengal. He played a significant role in various social reforms and fought against social evils, but he was not associated with the founding of the Prarthana Samaj.

Option 4, Keshab Chandra Sen, is also not the correct answer. Keshab Chandra Sen was a prominent figure in the Brahmo Samaj, another socio-religious reform movement. Though both the Prarthana Samaj and the Brahmo Samaj had similar goals, Keshab Chandra Sen was not directly involved in the founding of the Prarthana Samaj.

It is important to note