Final answer:
The Center of Mass moves forward and backward, and left and right during gait, aligning with the side-to-side (mediolateral) and back-to-front (anteroposterior) directions.
Step-by-step explanation:
The two directions in which the Center of Mass (COM) moves during gait are forward and backward, and left and right. This means the correct answer is d. Both b and c. When a person walks, the COM shifts in a three-dimensional path that resembles a slightly flattened oval shape, moving side-to-side (mediolateral) and back-to-front (anteroposterior) with each step. This movement occurs to maintain balance and provide efficiency during locomotion. It's worth noting that there is also vertical oscillation involved, but the question specifically asks about the horizontal directions of COM movement during gait.