As the number of surgeons increases faster than the number of surgeries, and at the same time, as surgical treatment without surgery is increasingly replacing surgical procedures, the average annual surgery volume of each surgeon has decreased by 1/4 in recent years. It can be inferred that This trend continues, and surgical levels will drop significantly. Which of the following assumptions is based on the above description? ['Unless a surgeon performs surgery at a certain minimum rate, it is impossible for his surgeon to maintain his medical skill properly.', 'Surgeons spend most of their time working on medications that do not require surgery.', 'All doctors, especially surgeons, are receiving less training in medical schools and lack innovative methods of implementation.', 'Due to the cause of the disease, the medical level of each surgeon has decreased in recent years.']