The correct answer is B) cumulatively compounded long-shunt. The cumulatively compounded long-shunt DC motor connection is the most commonly used scheme for DC compound motors. This configuration provides additional torque through the cumulative effect of the series and shunt field windings, making it well-suited for applications requiring high starting torque and speed regulation, such as machinery and traction motors. The other options are less common: A) differentially compounded long-shunt and C) differentially compounded short-shunt connections provide reduced starting torque, while D) cumulatively compounded short-shunt is less efficient than the long-shunt arrangement.