The correct answer is option 4: Yellow.

When green and red colors are combined, they create yellow. This is because green and red are primary colors in light and mixing them together produces yellow light.

In color theory, colors are often represented using the RGB color model, which stands for red, green, and blue. In this model, different colors are created by combining different intensities of these primary colors.

Green and red are positioned on opposite sides of the color wheel, and when they are mixed together, they cancel each other out and produce yellow. This is known as additive color mixing, where light is being combined.

It`s important to note that this combination of green and red to create yellow applies specifically to light and the RGB color model. In other color models like the CMYK color model used for printing, the combination of green and red would not produce yellow.

So, in conclusion, when green and red colors are combined in the RGB color model, the resulting color is yellow.