Circles should have a ______ mark and are dimensioned with a ______ to identify the ________.

The statement describes how circles are represented in technical drawings and engineering design. Circles typically have a center mark, which helps indicate the exact center from which measurements are taken. The use of a leader line is common for dimensioning, allowing for clear annotations without cluttering the drawing.

Dimensioning circles requires a measurement of their size, which is identified using the diameter. This is the distance across the circle through its center, which is the most straightforward way to express a circle's size in engineering and design practices.

This understanding is critical since accurate representation and dimensioning are vital for ensuring that parts fit together correctly in engineering design. The other options do not accurately capture the common conventions used for circles in technical drawings. For example, other terms like edge or hub may not relate directly to the established naming conventions and methods of denoting dimensions for circles.