9314
All the acetal - containing PEGs and PEG / protein conjugates were proven to degrade upon acidic treatment .
 Chemical: acetal; Chemical: PEGs; 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: acetal, PEGs, PEG 
Answer:
 Chemical: acetal; Chemical: PEGs; Chemical: PEG