According to the Chemical Data Guide, propylene oxide is assigned a health hazard rating of 3,2,2. The last digit "2" of the rating means ___________________.

A
chemical vapors will cause a slight smarting of the eyes or respiratory system if present in high concentrations
B
the chemical contains fairly severe skin irritants, causing second- and third-degree burns after a few minutes contact
C
the chemical poison presents some hazard if it enters the body and typically has threshold limits of 100 to 500 ppm
D
the chemical is severely hazardous, usually having threshold limits below 10 ppm
E