29892
He became a laboratory assistant to Thomas Edison in December 1879 , and assisted in the development of Edison 's incandescent electric light .
 person: Thomas Edison; person: Edison
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: Thomas Edison, Edison 
Answer:
 person: Thomas Edison; person: Edison