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: STATIONERY 
Clue: The card seen here is designed for use with this name brand
rolodex

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

Category: FAMOUS PAINTERS 
Clue: Alfred Stieglitz discovered her drawings & exhibited them in 1916 while she was teaching art in the south

georgia o\'keeffe