Hello to answer your question, It would be A.
B. is wrong because we can't survive off of just crops
C. is wrong because even if we could come up with good ideas, it would be impossible for the whole world to agree with somebodys idea
Signed by, Virtuoso Sargedog
The correct answer is option (a). Parent material
The soil horizon refers to distinct layers of the soils, which are parallel to one another, but have a different composition from the layer present above and below to it.
The soil horizon can be divided into four different layers. First one is organic layer, which is the topmost layer, below this layer second layer of topsoil is present. Below top soil, subsoil is present. Below subsoil, the bottom most horizon parent material is present.