Which feature of a CAD system aids in the alignment of parts with angled edges?

The chamfer feature in a CAD system is specifically designed to create a beveled edge on a part. This beveled edge can effectively facilitate the alignment of parts that have angled edges, as it creates a flat surface that can come into contact with other parts at specific angles. Such alignment is crucial in assemblies where precision fit and alignment are key to the functionality of the final product.

In contrast, the countersink option refers to creating a conical-shaped recess in a part, typically used for allowing a screw or bolt head to sit flush with the surface. While useful for certain applications, it does not specifically aid in aligning parts with angled edges.

Dimensions are essential for indicating the sizes and locations of features on a part, but they do not inherently alter the geometry of the part or assist in alignment.

The cutting plane line is used in technical drawings to indicate where an imaginary cut has been made to view interior features. While it is important for communication in design, it does not contribute to the physical alignment of parts.

Hence, the chamfer is the most suitable feature for aligning parts with angled edges, making it the correct choice.