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.

[Q]: Category: OPTICS 
Clue: On New Year's or any other day, it's the fineness of detail that can be distinguished in a photographic image
[A]: resolution


[Q]: Category: THE INSTRUMENT OF DEATH 
Clue: In 1793 Jean-Paul Marat was retired in the bath with one of these
[A]: a knife


[Q]: Category: U.S. PRESIDENTS 
Clue: His eldest son, also named Theodore, was governor of Puerto Rico from 1929 to 1932
[A]:
theodore roosevelt