To answer this question, you need to know who gave the title "Mahatma" to Gandhiji.
Option A) Rajendra Prasad - This option is incorrect because Rajendra Prasad did not give the title "Mahatma" to Gandhiji.
Option B) Rabindranath Tagore - This option is correct. Rabindranath Tagore is the one who gave the title "Mahatma" to Gandhiji. Tagore was a poet, philosopher, and Nobel laureate, and he bestowed this honor on Gandhiji as a mark of respect for his leadership and contributions to India's freedom struggle.
Option C) Chittaranjan Das - This option is incorrect. Chittaranjan Das was a political leader and a close associate of Gandhiji, but he did not give the title "Mahatma" to Gandhiji.
Option D) Subhash Chandra Bose - This option is incorrect. Subhash Chandra Bose was a prominent freedom fighter and leader, but he did not give the title "Mahatma" to Gandhiji.
The correct answer is B) Rabindranath Tagore. This option is correct because Tagore gave the title "Mahatma" to Gandhiji in recognition of his high moral character and leadership qualities.