Which fuze can only be set by hand?

The M732A2 fuze is unique in that it can only be set manually. This requirement for hand-setting is primarily due to its design and operational characteristics, which necessitate that a crew member physically adjust the setting of the fuze before the projectile is loaded into the cannon. Manual setting allows for precise configuration depending on the desired detonation mode, which may include options such as point detonation or delay settings.

In contrast, the other fuzes listed have different mechanisms for activation or can be set using automated systems. For instance, automated or electronic fuzes might allow for settings to be adjusted in a more streamlined manner, reducing the risk of error and speeding up the loading process. Therefore, the M732A2 stands out for requiring a hands-on approach to ensure proper functioning in accordance with operational needs.