To solve this question, the user needs to have knowledge about the founder of Arya Samaj.
Option A: Raja Ram Mohan Roy was not the founder of Arya Samaj. He was a social reformer who was known for his efforts to abolish the practice of Sati and promote women's education.
Option B: Dayanand Saraswati was the founder of Arya Samaj. He was a Hindu monk and social reformer who sought to purify Hinduism and return it to its Vedic roots.
Option C: Swami Vivekananda was a disciple of Ramakrishna and was known for his contributions to the revival of Hinduism in India. He was not the founder of Arya Samaj.
Option D: Annie Besant was a British socialist, theosophist, and women's rights activist. She was not the founder of Arya Samaj.