【单选题】

In ancient times the most important examinations were spoken, not written. In the schools of ancient Greece and Rome, testing usually consisted of saying poetry aloud or giving; speeches.

In theEuropean universities of the middleAges, students who were working for advanced degrees had to discuss questions in their field of study with people who had made a special study of the subject. This custom exists today as part of the process of testing candidates(考生) for the doctor’ s degree.
Generally, however, modern examinations are written. The written examination, where all students are tested on the same questions, was probably not known until the nineteenth century. Perhaps it came into existence with the great increase in population and the development of modern industry.A、room full of candidates for a state examination, timed exactly by electric clocks and carefully watched over by managers, resembles a group of workers at an automobile factory.Certainly, during examinations teachers and students is expected to act like machines.
One type of test is sometimes called an objective test. It is intended to deal with facts, not personal opinions. To make up an objective test the teacher writes a series of questions, each of which has only one correct answer.Along with each question the teacher writes the correct answer and also three statements that look like answers to students who have not learned the material properly.
The main idea of paragraph 3 is that______ .
A、workers now take examinationsB、the population has grown
C、there are only written exams todayD、examinations are now written and timed