Which kind of dimension is measured between two extension lines?

The correct choice pertains to the type of dimension involved when measuring the distance between two extension lines. This scenario typically relates to size dimensions, which provide a measurement of the physical extent of an object. Size dimensions are crucial in technical drawings as they communicate how large or small a particular feature or part of the object is.

Extension lines are used to indicate the limits of a dimension, helping to clarify the specific measurement being referenced. The dimension measured between these lines directly corresponds to the size of the feature in question, whether that be length, width, height, or diameter, depending on the context of the drawing. Therefore, when considering the relationship between extension lines and the type of dimension they define, size is the most fitting descriptor for what is being measured.

In contrast, location dimensions would specify the position of a feature relative to a datum or other reference points. Profile dimensions would indicate the outline or shape features of an object, and depth dimensions would measure how deep a feature extends into a substrate or material. Each of these serves a different purpose and is not specifically defined by the measurement between extension lines, which is exclusively about size.