With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: During the late 19th century the British also gained control of the north coast of Borneo, where the Dutch had found it overly difficult to ever establish their rule. Development on the Peninsula and Borneo were generally separate until the 19th century. The eastern part of this region (now Sabah) was under the nominal control of the Sultan of Sulu, who later became a vassal of the Spanish East Indies. The rest was the territory of the Sultanate of Brunei. In 1841, British adventurer James Brooke helped the Sultan of Brunei suppress a revolt, and in return received the title of raja and the right to govern the Sarawak River District. In 1846, his title was recognised as hereditary, and the "White Rajahs" began ruling Sarawak as a recognised independent state. The Brookes expanded Sarawak at the expense of Brunei.
text_B: Is English likely to be an official language in the northern parts of Borneo?
YES.