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: QUEEN ELIZABETH II 
Clue: It's Queen Elizabeth's official London residence
[A]: buckingham palace


[Q]: Category: EXPLORERS 
Clue: John Speke died just before he was to debate this former exploring partner on the source of the Nile
[A]: sir richard burton


[Q]: Category: REACH FOR THE STARS 
Clue: This constellation used to be the Claws of Scorpio (by the "weigh", scorpions don't have scales)
[A]:
libra