22553
Here , a heterobifunctional polyethylene glycol ( PEG ) was used as a spacer arm to conjugate meningococcal group Y capsular PS with tetanus toxoid ( TT ) .
 Chemical: polyethylene glycol; Chemical: PEG
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: polyethylene glycol, PEG 
Answer:
 Chemical: polyethylene glycol; Chemical: PEG