The word "hierarchy" in the 4th paragraph refers t

单项选择题

Because early man viewed illness as divine punishment and healing as purification, medicine and religion were inextricably linked for centuries. This notion is apparent in the origin of our word "pharmacy," which comes from the Greek pharmakon, meaning "purification through purging."
By 3500 B. C. , the Sumerians in the Tigris Euphrates valley had developed virtually all of our modern methods of administering drugs. They used gargles (漱口药), inhalations (吸入药), pills, lotions, ointments (药膏), and plasters. The first drug catalog, or pharmacopoeia, was written at that time by an unknown Sumerian physician. Preserved in cuneiform script on a single clay tablet are the names of dozens of drugs to treat ailments that still afflict us today.
The Egyptians added to the ancient medicine chest. The Ebers papyrus (paper made of grass), a scroll dating from 1900 B. C. and named after the German Egyptologist George Ebers, reveals the trail-and-error know-how acquired by early Egyptian physicians. To relieve indigestion, a chew of peppermint leaves and carbonates (known today as antacids) was suggested, and to numb the pain of tooth extraction, Egyptian doctors temporarily ease a patient with ethyl alcohol.
The scroll also provides a rare glimpse into the hierarchy of ancient drug preparation. The "chief of the preparers of drugs" was the equivalent of a head pharmacist, who supervised the "collectors of drugs," field workers who gathered essential minerals and herbs. The "preparers’ aides" (technicians) dried and ground ingredients, which were blended according to certain formulas by the "preparers." And the "conservator of drugs" oversaw the storehouse where local and imported mineral, herb, and animal-organ ingredients were kept.
By the seventh century B. C., the Greeks had adopted sophisticated mind-body view of medicine. They believed that a physician must pursue the diagnosis and treatment of the physical (body) causes of disease within a scientific framework, as well as cure the supernatural (mind) components involved. Thus, the early Greek physician emphasized something of a holistic approach to health, even if the suspected "mental" causes of disease were not recognized as stress and depression but interpreted as curses from displeased gods.
The modern era of pharmacology began in the sixteenth century, ushered in by the first major discoveries in chemistry. The understanding of how chemicals interact to produce certain effects within the body would eventually remove much of the guesswork and magic from medicine.
Drugs had been launched on a scientific course, but centuries would pass before superstition was displaced by scientific fact: one major reason was that physicians, unaware of the existence of disease causing something such as bacteria and viruses, continued to dream up imaginary evils. And though new chemical compounds emerged, their effectiveness in treating disease was still based largely on trial and error.
Many standard, common drugs in the medicine chest developed in this trial-and-error environment. Such is the complexity of disease and human biochemistry that even today, despite enormous strides in medical science, many of the latest sophisticated additions to our medicine chest shelves were accidental finds.

The word "hierarchy" in the 4th paragraph refers to ______.

A．the status of physicians in society
B．the division of labor
C．the process of drug preparation
D．the components of ancient drugs