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The first practical device that could amplify was the triode vacuum tube , invented in 1906 by Lee De Forest , which led to the first amplifiers around 1912 .
 person: Lee De Forest
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: Lee De Forest 
Answer:
 person: Lee De Forest