Q: 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: RELIGION 
Clue: An aid to the faithful since the 13th century, one standard version has parts arranged in groups of 1, 3 or 10
A:
the rosary