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.
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Question: Category: A DELICATE OPERATION 
Clue: A bypass operation may bypass the carotid or coronary one of these

Answer: artery


Question: Category: TELEVISION 
Clue: Ray Walston was the Martian while the "my" in "My Favorite Martian" referred to him

Answer: bill bixby


Question: Category: EUROPEAN CAPITALS 
Clue: In an August 1989 protest, a 2-million-person human chain stretched from Tallinn to Riga to this city

Answer:
vilnius