The founder of the Ramakrishna Mission, dedicated to social and spiritual teachings, was:

Correct option is C

The correct answer is Swami Vivekananda.
The founder of the Ramakrishna Mission was Swami Vivekananda. The Ramakrishna Mission was established in 1897 to spread the teachings of Vedanta, as embodied in the life of Ramakrishna Paramahamsa, and to improve the social conditions of India.