To qualify as a medical specialist, one must usually graduate from a university, then complete approximately four years of medical school, followed by a residency of two to six years in one' s specialty. Finally, a physician who desires to become a recognized specialist must complete an evaluation program directed by a medical specialty board. Ttherefore, anyone who has qualified as a recognized medical specialist is competent to practice in his or her specialty. Which one of the following is an assumption on which the argument depends? ['People who are not highly motivated will not complete the demanding course of study and examination required to become qualified as a recognized medical specialist.', 'Only the most talented people will successfully complete the rigorous course of study necessary for qualification as a recognized medical specialist.', 'Usually, six to ten years of medical training beyond a university degree is necessary to render someone competent to practice in his or her medical specialty.', 'No one incompetent to practice a particular specialty completes the evaluation program for that specialty.']