This determines how NX loads the component parts into an assembly, such as loading components fully or partially.

The correct answer is Assembly Load options, as this specifically refers to the settings that dictate how assembly components are loaded within Siemens NX. These options allow users to decide whether to load all components of the assembly completely or to load only certain components partially. This is particularly useful in managing large assemblies where loading every part may not be necessary for every task, thus enhancing performance and efficiency during design and modification processes.

Other options like System options, Selection options, and Modeling options do not pertain specifically to the assembly loading behavior. System options might include general preferences for the operating environment of NX, while Selection options typically relate to how selections are made within the user interface, and Modeling options focus on the settings pertinent to creating and modifying geometric models. Therefore, only Assembly Load options provide the specific control and capability related to the loading of parts in an assembly context.