What does the term 'Point System' refer to?

The term 'Point System' primarily relates to typography, specifically in the measurement of font sizes. Points are a standard unit of measurement used in the printing and typesetting industries, where one point is equal to 1/72 of an inch. This system allows designers and typographers to specify the height of typefaces, ensuring consistent sizing across different media.

While other options present various measurement systems, they do not pertain to typography. For example, methods for measuring length or calculating volume do not utilize points as a unit, and capacity units in the metric system refer to liters or milliliters rather than points. Thus, the connection of the 'Point System' to font size makes it the correct answer in the context of advertising design and typesetting.