[单选题]
An electric motor is used to raise51v golw6w*u f a b;8m.r7ivqe dgj vi 4m,lock of mass 18.0 kg vertically to the top ofmd.j7e, rmqg8vi4 vi; a building at a constant speed of $1.5\,ms^{−1}$. If the power rating of the motor is 297 W, calculate the efficiency of the motor.
