Correct Option (B)
The last significant territorial expansion of British India occurred during the tenure of Lord Dalhousie (1848-1856). This period is notable for the implementation of the Doctrine of Lapse, a policy that allowed the British East India Company to annex the princely states of Indian rulers who died without a natural male heir. Key annexations under this doctrine included Satara (1848), Jaitpur and Sambalpur (1849), Baghat (1850), Udaipur (1852), Jhansi (1853), and Nagpur (1854). Furthermore, Awadh was annexed in 1856 on the pretext of misgovernance, marking another major territorial acquisition.
Incorrect Options:
A) Lord Dufferin (1884-1888) oversaw the Third Anglo-Burmese War (1885), which resulted in the annexation of Upper Burma. While this was a territorial addition, it was not considered the "last major extension" in the context of the vast annexations under Dalhousie, particularly within the Indian subcontinent.
C) Lord Lytton (1876-1880) is primarily associated with the Second Anglo-Afghan War and internal administrative policies like the Vernacular Press Act and the Arms Act. His period did not involve major territorial extensions within British India.
D) Lord Curzon (1899-1905) focused on administrative reforms, the partition of Bengal, and foreign policy initiatives such as the Younghusband expedition to Tibet. No significant territorial annexations of Indian states occurred during his viceroyalty.