Consider the faulting illustrated here. In a normal fault, the block above the fault moves down relative to the block below the fault. This fault motion is caused by tensional forces. We might expect all BUT to occur at the sites of the faults.

Downward movement

Explanation:

In this question, the downward movement will be out of the question. This is because all the tension is directed in the horizontal direction. The tensional forces exist in the strings. This then gives rise to the force that then causes the blocks to move. In an ideal situation as this one, the string does not carry a mass. Therefore, the mass is negligible. In addition, there is no friction between the string and the surface. Thus, friction can be neglected as well. Thus, no downward motion is available.