C . Telegraph ..............
The sequence of events that can lead to magma becoming soil is C. crystallization followed by exposure and weathering. Under these circumstances it may happen that magma actually turns to soil - it cools off so much that it becomes the ground we walk upon.
You see how much the scale is, let's say that it is 150 mm=300 miles. If it goes over, you can measure it with a ruler, or move with your hands, measuring it as well as possible and estimating. Hope this helps! :)
