A scale will read a force value that is equal to the normal force exerted by the scale upon the object that is in contact with its top surface. By analyzing all the other forces that act upon that object, it is possible to predict a value for the scale reading.
 

The 5.0-kg box is above the scale and not touching it. Normal forces exist when two in-contact objects have their surfaces pressed together. For instance, if you sit on a chair cushion, gravity pulls you downwards and your body and the chair cushion are pressed together. This pressing together of the two surfaces causes the normal force. But if there is no contact then there is no pressing together of the surfaces. The result is that there is no normal force. 

This is the type of thinking you need to apply to this question. Now go answer it with confidence.