Forty-five fathoms is marked on the anchor chain by（）.

A.one turn of wire on the first stud from each side of the detachable link

B.two turns of wire on the second stud from each side of the detachable link

C.three turns of wire on the third stud from each side of the detachable link

D.four turns of wire on the fourth stud from each side of the detachable link

数字视频的数据量非常大，VCD使用的运动视频图像压缩算法MPEG-1对视频信息进行压缩编码后，每秒钟的数码率大约是【 】Mbps。