Explanation:

- Lord Dalhousie annexed Awadh in 1856 under the Doctrine of Lapse, citing internal mismanagement as the reason.

- The Doctrine of Lapse was a policy of annexation applied by the British in India.

- Option 1, 1857, is historically significant for the Indian Rebellion, but not related to Awadh’s annexation.

- Option 2, 1855, does not align with any major event related to Awadh’s annexation.

- Option 3, 1858, marks the end of the Indian Rebellion and the transition to direct British rule but is unrelated to the annexation of Awadh.

- Option 4, 1856, is indeed the correct answer.

Option 4: 1856