The correct answer is option 2 - Annie Besant. She founded the Central Hindu School at Benaras, which later became the Benaras Hindu University.

Option 1 - Madan Mohan Malaviya was a prominent Indian educationist and politician, but he did not found the Central Hindu School or Benaras Hindu University. However, he played a crucial role in developing and expanding the university after its establishment.

Option 3 - Ishwar Chandra Vidyasagar was a renowned Bengali scholar and social reformer. He made significant contributions to education reforms in India, particularly in Bengal, but he was not associated with the founding of the Central Hindu School or Benaras Hindu University.

Option 4 - Madame H.P. Blavatsky was a Russian occultist, philosopher, and author but she was not involved in the establishment or development of the Central Hindu School or Benaras Hindu University.

In summary, Annie Besant was the one who founded the Central Hindu School at Benaras, which eventually evolved into the Benaras Hindu University.