2940
Potomac Airfield is located in the Flight Restricted Zone ( FRZ ) in the center of the Washington , D.C. Air Defense Identification Zone .
 location: D.C.
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 location: D.C.