The right option is; a. soil excavation and disposal
Soil remediation refers to various methods used to remove contaminants from soil. Soil excavation and disposal is a method of soil remediation in which contaminated materials (soil) is removed (by digging) from its original position and disposed in a landfill or transported to an authorized off site treatment facility. This method can affect the soil profile by damaging root channels, vegetation and soil horizon. It can also expose soils to high level of wind and water erosion.