74852
Walker Digital 's practice of acquiring patents and litigating against companies whom they feel have infringed upon them have caused it to be popularly labeled as a patent troll .
 person: Walker Digital
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: Walker Digital 
Answer:
 person: Walker Digital