The number of pixel columns divided by the number of scan lines that can be displayed by the system, is called

Explanation

Aspect ratio in raster graphics is defined as the ratio of the width (number of pixel columns) to the height (number of scan lines/rows) of a display. A pixmap and a bitmap are data structures that store per-pixel color/intensity values (multi-bit and 1-bit per pixel respectively), not a ratio, and depth refers to the number of bits used to represent each pixel. Since the question describes a width-to-height ratio, the correct term is Aspect ratio.