Explanation:

- In 1856, the Governor-General of India took a significant decision regarding the Mughal dynasty's future.

- This decision stated that Bahadur Shah Zafar would be the last Mughal emperor, and his descendants would only be recognized as princes, not kings.

- Option 1: Canning

- Lord Canning was the Governor-General of India from 1856 to 1862.

- He was responsible for several important decisions, including the policy concerning the Mughal dynasty.

- Correct Answer: Canning

- Option 2: Cornwallis

- Lord Cornwallis was the Governor-General much earlier, serving from 1786 to 1793.

- Option 3: Hastings

- There were two Governor-Generals with this name. Warren Hastings served in the late 18th century, and Francis Rawdon-Hastings served in the early 19th century.

- Option 4: Munro

- Thomas Munro was known for his work in the Madras Presidency, not as a Governor-General of India.