A.
The above code indicates that the background color is red, the image is centered, the size is 50%, and the image is not repeated.
B.
If no-repeat is deleted, the image will not repeat.
C.
If the element url("../image/author-1.jpg") is deleted, a red background will be displayed.
D.
If no-repeat is changed to repeat-x, the image is horizontally repeated.