One person was doing a knee extensor muscle training, he used a dumbbell (mass = 10.2 kg) strapped to the ankle
joint and was 0.4 m from the knee joint (see attached figure). The dumbbell was 0.3 m away from the knee joint in the horizontal direction.
How large was the torque generated by the dumbbell weight about his knee joint?
A.) 50 Nm
B.) 40 Nm
C.) 26 Nm
D.) 30 Nm