You Can Use One of the Options in the Background

You can use one of the options in the Background Styles gallery to change the background of slides to which of the following?

A) Variations of two of the colors in the theme colors palette plus black and white.
B) Variations of one color in the theme colors palette plus black and white.
C) Different shades and gradients of black.
D) Any of the 12 colors in the theme colors palette.