请阅读Passage 1，完成第小题。
Passage 1
The British Medical Journal recently featured a strong response to what was judged an inappropriately lenient reaction by a medical school to a student cheating in an examination.
Although we have insufficient reliable data about the extent of this phenomenon, its prevention, or its effective management, much can be concluded and acted upon on the basis of common sense and concepts with face validity.
There is general agreement that there should be zero tolerance of cheating in a profession based on trust and one on which human lives depend. It is reasonable to assume that cheaters in medical school will be more likely than others to continue to act dishonestly with patients,colleagues, insurers, and government.
The behaviours under question are multifactorial in origin. There are familial, religious, and cultural values that are acquired long before medical school. For example, countries, cultures, and subcultures exist where bribes and dishonest behaviour are almost a norm. There are secondary schools in which neither staff nor students tolerate cheating and others where cheating is rampant;there are homes which imbue young people with high standards of ethical behaviour and others which leave ethical training to the harmful influence of television and the market place.
Medical schools reflect society and cannot be expected to remedy all the ills of a society. The selection process of medical students might be expected to favour candidates with integrity and positive ethical behaviour--if one had a reliable method for detecting such characteristics in advance. Medical schools should be the major focus of attention for imbuing future doctors with integrity and ethical sensitivity. Unfortunately there are troubling, if inconclusive, data that suggest that during medical school the ethical behaviour of medical students does not necessarily improve;indeed, moral development may actually stop or even regress.
The creation of a pervasive institutional culture of integrity is essential. It is critical that the academic and clinical leaders of the institution set a personal example of integrity. Medical schools must make their institutional position and their expectations of students absolutely clear from day one. The development of a school's culture of integrity requires a partnership with the students in which they play an active role in its creation and nurturing. Moreover, the school's examination system and general treatment of students must be perceived as fair. Finally, the treatment of infractions must be firm, fair, transparent, and consistent.

What does the author say about cheating in medical schools?
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A．Extensive research has been done about this phenomenon.
B．We have sufficient data to prove that prevention is feasible.
C．We are safe to conclude that this phenomenon exists on a grand scale.
D．Reliable data about the extent, prevention and management of the phenomenon is lacking.