Which Synchronous Modeling command can be used to modify a body by adding or subtracting faces of a sheet body?

The option that accurately identifies the Synchronous Modeling command used to modify a body by adding or subtracting faces of a sheet body is the choice that refers to "Paste Face." This command allows users to take faces from one body and effectively transfer them to another, facilitating the modification of 3D geometries through direct manipulation of surfaces.

By utilizing "Paste Face," users can integrate or eliminate features and details more seamlessly, which is fundamental in scenarios where precision and adaptability are required, particularly in processes involving sheet bodies. This command stands out because it focuses on the direct interaction with faces of an existing geometry, enabling the body modification to follow the designer's intent directly.

In contrast, the other commands mentioned serve different purposes. The "Add/Remove Face" command focuses on the addition or removal of entire faces rather than specifically on the process of pasting from one geometry to another. "Boolean Face," while it does interact with faces, typically involves creating combined geometries through union or intersection operations instead of straightforward face modification. "Paste Special" refers to a command mainly for copying and pasting features rather than directly modifying the geometry in the way described in the question.

The specificity and functional application of "Paste Face" align perfectly with the task