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: THEY EAT THAT? 
Clue: A food stand by London's Petticoat Lane is called, & serves, "Jellied" this elongated fish
eel

Category: WHO PLAYED 'EM ON TV? 
Clue: Army company clerk Radar O'Reilly
gary burghoff

Category: TEX-ARCANA 
Clue: Big Bend National Park is on a Big Bend of this river in western Texas

the rio grande