3165
A control co - oligomer ( P2 ) possessing similar structure to P1 was also prepared , but in this case the OPE bears no side chains .
 Chemical: OPE
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: OPE 
Answer:
 Chemical: OPE