In the very beginning, a brief introduction is always given. It should include at least four pieces of information: what you’re going to talk about; how long you’ll take; _____________; whether you’d welcome questions during your talk, or only at the end.
选项：

A:
A: what your main parts or sections will be;;
B:
B: your purpose;;
C:
C: your stuff member;;
D:
D: your target audience.