Aromatherapy is a term used to describe the practice of using essential oils taken from plants, flowers, roots, seeds, etc., in healing. The term is a bit misleading, since the aromas of oils, whether natural or synthetic, are generally not themselves therapeutic. Aromas are used to identify the oils, to determine adulteration, and to stir the memory, but not to directly bring about a cure or healing.
The above argument assumes that:
The healing power of essential oils is the main draw in aromatherapy.
Aromatherapy may have a number of uses. The given paragraph/argument assumes that a cure or healing power of the oils is the main attraction. Hence, option (d) is the correct answer.