A research institute proposed that wet sand was the key to the ancient Egyptians to carry huge stones and statues in the desert. Researchers pointed out that the ancient Egyptians placed heavy stones after the skid and laid a layer of wet before the skid This kind of handling method has an unexpected effect. In the experiment, the researchers used a rheometer to test the hardness of the sand to confirm how much traction is needed to deform a certain amount of sand, and based on this The traction model was designed on it, and it was found that it is easier to move heavy objects when the wet sand is spread before the skid, and the moisture content of the sand determines the hardness and traction of the sand. Which of the following, if true, would best support the above conclusion. ['In a mural of an ancient Egyptian tomb, a man stands in front of a skid and seems to be watering.', 'Traction force is inversely proportional to the hardness of the sand, and the hardness of the wet sand is twice that of the dry sand.', 'The experiment proves that the wet sand laid before the skid is easy to accumulate, forming a large sliding resistance.', 'A laboratory version of the Egyptian skid was successfully constructed, which can simulate the actual conditions of an ancient Egyptian construction site.']