There are some principles for us to follow when it comes to starting with a definition in the opening paragraph. Choose the one which is not correct.
选项：

A:We’d better write a clear-cut and concise definition with key points.;
B:We’d better make the definition as extended as possible.;
C:We’d better use our own definition because it is uniquely created.;
D:We’d better write no more than three sentences for a definition.