The correct answer is: a) Restoring Sikkimese territory from Nepal.
The Treaty of Titalia was signed on 15 March 1817 between the British East India Company and the Kingdom of Sikkim. The treaty was a result of the Anglo-Nepalese War (1814-1816), in which the British defeated Nepal. The treaty restored Sikkimese territory that had been occupied by Nepal during the war. The treaty also established British control over Sikkim’s foreign affairs.
Option b is incorrect because the treaty did not establish British control over Sikkim. The treaty only established British control over Sikkim’s foreign affairs.
Option c is incorrect because the treaty did not abolish the Namgyal Dynasty. The Namgyal Dynasty continued to rule Sikkim until 1975.
Option d is incorrect because the treaty did not grant Sikkim full independence. The treaty only restored Sikkimese territory that had been occupied by Nepal and established British control over Sikkim’s foreign affairs.