63988
Upside-down artificial Christmas trees became popular for a short time and were originally introduced as a marketing gimmick ; they allowed consumers to get closer to ornaments for sale in retail stores and opened up floor space for more products .
 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