The correct answer is: A. Right
Signals are normally located to the right side of the line. This is because most people are right-handed, and it is easier for them to see and operate signals that are located on the right side of the road. Additionally, signals that are located on the right side of the road are less likely to be obstructed by trees, buildings, or other objects.
Option B is incorrect because signals are not normally located to the left side of the line. This is because most people are right-handed, and it is easier for them to see and operate signals that are located on the right side of the road. Additionally, signals that are located on the left side of the road are more likely to be obstructed by trees, buildings, or other objects.
Option C is incorrect because signals are not normally located on both sides of the line. This is because it would be confusing for drivers to have to look for signals on both sides of the road. Additionally, it would be more expensive to install signals on both sides of the road.
Option D is incorrect because signals are normally located to the right side of the line.