What are the three types of an abstract?

A.An indicative abstract, an informative abstract and an indicative-informative abstract.

B.An indicative abstract, a descriptive abstract, and an indicative-informative abstract.

C.An indicative abstract, a descriptive abstract, and an informative abstract.

D.None of the above.

正确答案：An indicative abstract, an informative abstract and an indicative-informative abstract.