What two types of maintenance are performed without distinction as to levels?

The correct answer focuses on the maintenance activities that can be performed without distinguishing between different levels of maintenance. Rework and upkeep represent tasks that are crucial in maintaining equipment but may not vary significantly in their execution processes regardless of the context or specific level.

Rework typically involves correcting or redoing work to ensure standards are met, which can apply equally to different levels of maintenance, such as between organizational or intermediate levels. Similarly, upkeep refers to ongoing maintenance activities aimed at preserving equipment functionality and performance, which also do not require a differentiation in levels.

In contrast, other choices encompass maintenance types that inherently imply specific levels or functions. For example, inspection is a critical first step that typically aligns with defined maintenance levels, and preventive and corrective maintenance connect directly to the understanding of scheduled versus unscheduled maintenance, which usually denotes methodological differences in execution. Therefore, the emphasis on rework and upkeep as two maintenance types that can be applied across different contexts makes this choice the most accurate in the context given.