Pandita Ramabai is the correct answer to the question. She established the `Sharda Sadan`, a school for Indian widows in colonial India. It is important to note that Mahadev Govind Ranade was a social reformer and scholar in colonial India, but he was not associated with the establishment of `Sharda Sadan`. Sarojini Naidu was a prominent Indian freedom fighter and politician but she was not involved in the establishment of the school for Indian widows. Dayanand Saraswati was a Hindu religious leader and founder of the Arya Samaj, but he did not establish `Sharda Sadan` either. Therefore, option 4, Pandita Ramabai, is the correct answer.