Which one of the following scales on a given map remains the same when it is enlarged or reduced?

Correct option is A

Introduction
The Graphical Scale (or Bar Scale) is the only type of map scale that remains valid when the map is photographically enlarged or reduced. Since the bar scale is a line drawn on the map, it changes in length in the same proportion as the map itself is enlarged or reduced, ensuring that the ratio between the map distance and the ground distance remains correct.
Information Booster
· Definition: A line or bar drawn directly on the map that is subdivided and marked to show the corresponding ground distance.
· Invariance: The length of the bar scale changes in direct proportion to the change in the size of the map.
· Practical Use: Because it changes with the map size, it is the most reliable scale for use with a map that has been resized, unlike verbal or representative fraction scales.
· Scale Representation: It represents the ratio of a distance on the map to the actual distance on the ground.
· Alternative Names: Also known as a Bar Scale or Linear Scale.
Additional Points
· Old Scale: Not a standard type of scale.
· Statement Scale: Expressed as a statement (e.g., "1 cm represents 1 km"); this becomes incorrect if the map is resized.
· Representative Fraction Scale: Expressed as a fraction or ratio (e.g., 1:50,000); this ratio is valid only for the original map size and becomes incorrect if the map is resized.