Final answer:
The relationship between external alchemy (waidan) and internal alchemy (neidan) is best described by their different focuses: external alchemy concentrates on manipulating physical substances, while internal alchemy prioritizes spiritual transformation and alignment with the Dao through personal practices.
Step-by-step explanation:
The statement that BEST represents the relationship between external alchemy (waidan) and internal alchemy (neidan) is: A) External alchemy focuses on physical substances, while internal alchemy focuses on spiritual transformation. External alchemy, or waidan, pertains to the Daoist alchemical practices that involve the manipulation of physical substances with the aim of creating an elixir of immortality or transforming base metals into gold, representing a quest for physical longevity and material success.
In contrast, internal alchemy, or neidan, represents a spiritual pursuit where the individual focuses on personal spiritual and physical refinement with practices such as meditation, breath control, and moral development to attain spiritual immortality and harmony with the Dao. Neidan practices aim to realize a profound transformation within the practitioner's body and consciousness, aligning them with the natural order, or Dao.