Answer:
The most appropriate answer would be "add sand to the soil".
In silty clay soil, the percentage of silt, clay, and sand are 60-70%, 40-30%, and 10-30%.
In contrast, in sandy clay loam, the percentage of silt, clay, and sand are 65-80%, 20-40%, and 60-95%.
Thus, Matt should add sand to the soil in order to convert it into a sandy clay loam soil by which the growth of the corn plants would increase.
