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.

Category: HUMANITARIAN LADIES 
Clue: Throughout the 1930s, she taught geography at St. Mary's High School in Eastern India
mother theresa

Category: ASTRONOMY 
Clue: A galactic cloud of dust & gas, its name comes from the Latin for "cloud"
nebula

Category: GEOMETRY 
Clue: A pentadecagon is a polygon with this many sides

15