Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

This island's Danum Valley Conservation Area is the only known home of the spectacled flowerpecker. Anthony Brooke was the heir apparent to the White Rajahs, a dynasty of Englishmen who controlled a kingdom on this island from 1841 to 1946. The Mahakam River flows past the city of Samarinda before emptying into the Makassar Strait, which separates Sulawesi from this island. The southern portion of this island is known as Kalimantan, and its northern portion contains the states of Sabah and Sarawak and an independent kingdom ruled by a sultan. For 10 points, name this Southeast Asian island divided between Malaysia, Indonesia, and Brunei.
Social Science