The correct answer is D) series wound. Series wound DC motors are never connected to a belt-driven load because they have very high starting torque and low speed characteristics. This high starting torque can cause the belt to slip or break if connected directly to a load. In contrast, shunt wound, compound wound, and permanent magnet DC motors have lower starting torque and are more suitable for belt-driven applications. Series wound motors are typically used for direct-drive applications that do not involve belts, such as electric vehicles, cranes, and hoists.