Explanation:

The **Prarthana Samaj** was founded in 1867 in Bombay (now Mumbai) by **Atmaram Panduranga**. It emerged as a reformist movement within Hinduism, inspired by the Brahmo Samaj, and sought to promote monotheism, social reforms, and religious practices based on reason and devotion. Its objectives included the abolition of the caste system, promotion of women's education, and widow remarriage. Option A is correct. Option B, Dayanand Saraswati, founded the Arya Samaj in 1875, advocating a return to the Vedas and emphasizing social reforms. Option C, Swami Vivekananda, was a chief disciple of Ramakrishna Paramahamsa and founded the Ramakrishna Mission in 1897, focusing on spiritual and humanitarian service. Option D, Sri Ramana Maharshi, was a renowned Indian sage and jivanmukta who taught the path of self-inquiry (Atma-vichara) in the early 20th century, but he was not a founder of a formal reformist organization like the Prarthana Samaj.