The correct answer is (c) Ishwarchandra Vidyasagar.
Ishwarchandra Vidyasagar was a Bengali polymath who is considered one of the greatest reformers of 19th-century India. He was a pioneer in the field of education and social reform, and he played a major role in the abolition of sati (widow burning) and the legalization of widow remarriage.
Raja Rammohan Roy was a Bengali polymath and social reformer who is considered one of the most influential figures in Indian history. He was a pioneer in the field of education and social reform, and he played a major role in the establishment of the Brahmo Samaj, a Hindu reform movement.
Kishan Chandra Sen was a Bengali poet, writer, and social reformer. He was a pioneer in the field of education and social reform, and he played a major role in the establishment of the Young Bengal movement, a group of young Bengali intellectuals who advocated for social and political reform.
Pandit Guru Dutt was a Bengali scholar and social reformer. He was a pioneer in the field of education and social reform, and he played a major role in the establishment of the Hindu Mela, a religious and cultural festival.
All of these figures were important reformers in 19th-century India, but Ishwarchandra Vidyasagar was the greatest supporter of widow remarriage. He argued that widow remarriage was a necessary reform to improve the lives of widows and to prevent them from becoming social outcasts. He also argued that widow remarriage was consistent with Hindu scriptures. In 1856, he successfully lobbied the British government to pass the Hindu Widow Remarriage Act, which legalized widow remarriage in India.