41935
Several rare but painful episodes of assassination , attempted assassination and school shootings at elementary , middle , high schools , as well as colleges and universities in the United States , led to a considerable body of research on ascertainable behaviors of persons who have planned or carried out such attacks .
 location: 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: United States 
Answer:
 location: United States