How should the variable xPosition be updated to draw touching columns of circles?

To draw touching columns of circles, it is important to understand the layout and spacing of the circles relative to their radius. Each circle has a diameter, which is twice the radius (2 * RADIUS). When positioned in a vertical or horizontal arrangement, the centers of adjacent circles should be spaced apart by this diameter to ensure they touch without overlapping.

In the context of updating the variable xPosition to start drawing the next circle directly next to the current one, you would indeed need to add 2 * RADIUS to the current xPosition. This adjustment ensures that the center of each new circle is positioned exactly at the edge of the previously drawn circle, creating a touching effect rather than an overlapping one.

This way, if you place the first circle at xPosition, the next circle's center will be at xPosition + 2 * RADIUS, resulting in the two circles just touching each other. Hence, selecting the option that updates xPosition by adding 2 * RADIUS achieves the desired outcome of drawing touching columns of circles.