Amines are organic compounds composed of amino groups and alkyl groups, which have been studied in university. If the landlord is in high school and doesn't take part in the competition, you don't need to know. The chemical formula of p-phenylenediamine is two -NH2 and one benzene ring, and the chemical formula is H2n-C6H5-NH2. Just draw a picture yourself, so the chemical formula is C6H8N2, so it can be calculated that the relative molecular weight is 65438. Dyeing hair is harmful to the body, so it can be absorbed by the skin. So for D, the carbon-oxygen ratio is 6* 12/8*2/2* 14, which is 18/2/7, so C is incorrect.