Correct option is B
Ishwar Chandra Vidyasagar, a prominent social reformer, was a pioneer in the field of women's education in India. He established the first girls’ school in Calcutta (now Kolkata) during the 19th century and worked toward women's upliftment.
Explanation of options: (a) ✘ Madras was a British presidency, but Vidyasagar's reform efforts were rooted in Bengal. (b) ✔ Calcutta was the hub of his educational and social reform movements. (c) ✘ Delhi was not a center of his activity; he primarily worked in Bengal. (d) ✘ Poona was a reform hub for others like Jyotiba Phule, not Vidyasagar.