Which one of these are not a type of hole you can create?

In the context of hole types in CAD software like Siemens NX, the correct option identifies a type of feature that does not fall under the standard categories of holes used in mechanical design. Clearance holes, internal threads, and external threads are all specific types of holes or features that serve distinct purposes within assemblies and component design.

Clearance holes are typically used to allow a fastener, like a bolt, to pass through without contacting the sides, ensuring that the assembly can be sufficiently adjusted or aligned. Internal threads are created within a hole to allow for a screw or bolt to screw in securely, facilitating tightening and assembly. Similarly, external threads are formed on the outside of a cylindrical feature, typically done to enable mating with a corresponding internal thread.

On the other hand, exit chamfers do not qualify as a hole type; instead, they are features that are used to provide a beveled edge at the end of a hole or at the termination of a shaft or edge. Their purpose is to ease the entry of fasteners and tools or to reduce stress concentration, rather than functioning as a hole itself. Thus, exit chamfers do not represent a classification of holes that can be created within a design context, making this option the correct choice.