Explanation:

- Resolution: This refers to the number of pixels displayed on the screen, defining image clarity and detail. Commonly in pixels such as 1920x1080. Correct Answer: Option 2 - Resolution. ""

- Color depth: This indicates the number of bits used for color in a single pixel, affecting the range of colors displayed.

- Refresh rate: This is the number of times a screen updates its image per second, measured in Hertz (Hz), affecting motion smoothness.

- Viewing size: This refers to the physical dimensions of the screen, often measured diagonally in inches.

Option 2 is the correct choice for the definition of the number of pixels displayed.