Concept:Arya Samaj is a Hindu reform movement founded by Swami Dayanand Saraswati in the 19th century.
Explanation:Swami Dayanand Saraswati started the Arya Samaj in 1875 at Bombay.
Swami Vivekananda founded the Ramakrishna Mission in 1897, not the Arya Samaj.
Raja Ram Mohan Roy established the Atmiya Sabha in 1815, which was a precursor to the Brahmo Samaj.
Ramakrishna Paramahansa was a mystic and spiritual teacher, but he did not found the Arya Samaj.
Thus, only Swami Dayanand Saraswati is the correct founder.
Answer:Option A – Swami Dayanand Saraswati