Determine the soil texture for the following combinations of sand, silt, and clay.

a. Sand 20 percent; Silt 20 percent;Clay 60 percent: __________
b. Sand 60percent; Silt 30percent; Clay 10percent: __________
c. Sand 50percent; Silt 10percent;Clay 40 percent: __________
d. Sand 80 percent; Silt 15 percent; Clay 5percent:__________