The correct answer is A. Large particles with air spaces.
Sandy soils are composed of large particles of sand, which are larger than silt and clay particles. These large particles have a lot of air spaces between them, which makes sandy soils well-drained and low in nutrients. Sandy soils are also not very good at retaining water, so plants that grow in sandy soils need to be drought-tolerant.
Option B is incorrect because fine particles have a smaller surface area than large particles, which means that they are not as good at holding water. Option C is incorrect because sandy soils have a low clay content, which means that they do not have a lot of nutrients. Option D is incorrect because sandy soils have a loose and open structure, which means that they are not compact or dense.