You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Example Input: Category: HEAVY MACHINERY 
Clue: By definition it's a machine that gives a surface an even degree of slope
Example Output: grader

Example Input: Category: GEOGRAPHY 
Clue: This Sudanese capital is located at the junction of the Blue & the White Nile
Example Output: khartoum

Example Input: Category: THE MOON 
Clue: On Dec. 24, 1968 the crew from this U.S. lunar mission became the first men to look upon the moon's far side
Example Output:
apollo 8