The following naming statements about benzene series are wrong: (a) The naming of benzene series must take benzene as the parent and other groups as the extraction.

A. In the naming of benzene series, benzene is usually used as the matrix, but when the substituent is complex, it is sometimes named with benzene as the substituent, so A is wrong;

B. Xylene can also be named in a systematic way. For example, the systematic nomenclature of o-xylene is: 1, 2- xylene, so b is correct;

C xylene is named o-xylene, m-xylene and p-xylene according to the customary nomenclature, so c is correct;

D. There are four isomers of aromatic hydrocarbons with molecular formula C8H 10, namely ethylbenzene, o-xylene, m-xylene and p-xylene, so D is correct;

So choose a.