Concept:The Peshwa was the prime minister of the Maratha Empire. The ruler of Kanpur who declared himself Peshwa was Nana Saheb.
Explanation:Nana Saheb, originally named Balaji Baji Rao, was the adopted son of Peshwa Bajirao II.
He lived in Bithoor, Kanpur district, after the Third Anglo-Maratha War.
When Bajirao II died, the British refused to accept Nana Saheb as his heir and stopped his pension.
This led him to join the Revolt of 1857.
He attacked the British at Kanpur, captured it, and declared himself Peshwa under Emperor Bahadur Shah Zafar.
Thus, Nana Saheb is the correct answer.
Answer:A. Nana Saheb