29372
The main source of this trans-border pollution results from coal-fired power stations , most of them located in the Midwestern United States .
 location: Midwestern United States
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: Midwestern United States 
Answer:
 location: Midwestern United States