20122
The mechanisms that can account for the remarkable mammary carcinogenicity of the environmental pollutant 6 - nitrochrysene ( 6 - NC ) in the rat remain elusive .
 Chemical: 6 - nitrochrysene; Chemical: 6 - NC
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: 6 - nitrochrysene, 6 - NC 
Answer:
 Chemical: 6 - nitrochrysene; Chemical: 6 - NC