76510
Specifically , he has been concerned with understanding aggregate economic fluctuations , studying the causes and consequences of exchange rate fluctuations , as well as the effect of monetary policy on postwar United States business cycles .
 None
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:  
Answer:
 None