Explanation:

Surdas (Correct): Surdas was a 16th-century blind devotional poet and singer, known for his works dedicated to Lord Krishna. He composed the 'Sur Sagar', 'Sur Saravali', and 'Sahitya Lahari', which primarily describe the life and pastimes of Krishna, especially his childhood. He lived in the Agra region and was a prominent figure of the Bhakti movement. Tulsidas: He was a great Hindu poet-saint of the 16th century, renowned for his devotion to Lord Rama and authoring 'Ramcharitmanas'. He was not blind and focused on Rama, not Krishna. Chaitanya: Chaitanya Mahaprabhu (1486–1534) was a 15th-century Indian saint who founded Gaudiya Vaishnavism and popularized the chanting of the Hare Krishna mantra. He was a spiritual leader from Bengal, not a blind poet from Agra. Ramanujan: Srinivasa Ramanujan (1887–1920) was a brilliant Indian mathematician, not a poet, and lived much later.