Answer: Option [B]If the size of an individual particle in the soil has a diameter of less than 0.002 mm, the soil is known as Clay. Soil particles vary greatly in size, and soil scientists classify soil particles into sand, silt, and clay. Starting with the finest, clay particles are smaller than 0.002 mm in diameter. Some clay particles are so small that ordinary microscopes do not show them. Silt particles are from 0.002 to 0.05 mm in diameter.