You will be given a definition of a task first, then some input of the task.
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.

The Keo Nua Pass in this country is one of the few passes through the Annamese Cordillera (CORE-dee-YARE-uh). This nation's capital includes the Temple of the Trung Sisters and is located on the Red River. The imperial citadel of Dai Noi is found in this country's onetime capital Hue (hway). For 10 points, name this Southeast Asian nation that was reunified in 1975 after a bloody war between the communist north and U.S.-aligned south.
Output:
Social Science