一道GRE逻辑题不会Hastings‘ contracture is a disorder of the connective tissue in one or both hands, most commonly causing loss of mobility. A survey of thousands of medical-insurance claims found that over 30 percent of people who had one hand operated on for Hastings'contracture underwent surgery a second time for this disorder within three years. Clearly, therefore, a single surgical treatment of Hastings' contracture is often ineffective at providing long

一道GRE逻辑题不会
Hastings‘ contracture is a disorder of the connective tissue in one or both hands, most commonly causing loss of mobility. A survey of thousands of medical-insurance claims found that over 30 percent of people who had one hand operated on for Hastings'contracture underwent surgery a second time for this disorder within three years. Clearly, therefore, a single surgical treatment of Hastings' contracture is often ineffective at providing long-term correction of the disorder
Which of the following, if true, most seriously weakens the argument? (A) The medical-insurance claims did not specie whether the surgery was on the patient's right or left hand. (B) The surgical techniques used to treat Hastings' contracture are identical to those used successfully to treat certain work-related injuries to the hand. (C) A separate survey found that 90 percent of patients operated on for Hastings' contracture report increased hand mobility within one month after the surgery. (D) All of the patients in the survey were required by their insurance companies to seek a second opinion from a qualified surgeon before undergoing the operation. (E) Many people who have Hastings' contracture choose to tolerate its effects rather than undergo the risks of surgery.
答案是A,CD为何不对呢?排除它因?