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: DIMENSIONS 
Clue: Don't lose the thread--there are 10 or so dimensions in this physics theory
string theory

Category: LITERATURE 
Clue: The first sequel to this classic French novel was titled "Twenty Years After"
the three musketeers

Category: THE SPANISH-AMERICAN WAR 
Clue: Clara Barton, who had lunch on this ship a few days earlier, was in her Red Cross office when it exploded

the maine