Which workers may be switched from their original assignment to any work on docks?

Longshoremen are the correct choice for this question because they are the workers directly involved in the loading and unloading of cargo at docks. They are specifically trained to perform various tasks associated with dock work, which makes them versatile and capable of switching assignments as needed. This flexibility is crucial in the dock environment, where operational demands can change rapidly depending on shipping schedules and cargo types.

Switching assignments among longshoremen enhances efficiency and safety in dock operations, allowing for the effective allocation of labor resources. Other options listed, such as supervisors, management staff, and office workers, typically have more defined and often stationary roles related to oversight, administration, or clerical tasks. These roles do not usually involve the physical dock work that longshoremen perform, resulting in their assignments being less fluid compared to that of longshoremen.