答案及解析：[单选题]There are many forms of online advertising.______is a small rectangular object on a Web page that di - 软件水平题库- 答案窝(daanwo.com)-大学生作业答案及考资分享平台

问题：

[单选题] There are many forms of online advertising.______is a small rectangular object on a Web page that displays a stationary or moving graphic and includes a hyperlink to the advertiser's Web site.
A.A text ad
B.A site sponsorship ad
C.A pop-up ad
D.A banner ad