15854
In this study we have conducted a comparative analysis of the toxicity of perfluorinated carboxylic acids ( PFCA ) with a carbon chain length ranging from four to twelve carbon atoms .
 Chemical: perfluorinated carboxylic acids; Chemical: PFCA; Chemical: carbon; Chemical: carbon
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: perfluorinated carboxylic acids, PFCA, carbon, carbon 
Answer:
 Chemical: perfluorinated carboxylic acids; Chemical: PFCA; Chemical: carbon; Chemical: carbon