Explanation

Steam distillation is the primary method used to obtain essential oils because it uses steam to vaporize the plant material. Extractive distillation is a process that usually requires adding a solvent or oil to help with vaporization. Solvent extraction involves using solvents like alcohol or hexane, which are different from standard essential oil methods. Leaching typically refers to washing materials with water or other liquids, not the primary method for essential oils.