[单选题]攀登训练必须严格遵守操作规程，严格检查保护设施，保护人员不得少于（）人，且必须时刻保持精力集中，下方应设置缓冲垫。
A.2
B.3
C.4

Last week’s news that scientists had cloned a sheep sent academics and the public into a panic at the prospect that humans might be next. That’s an understandable reaction. Cloning is a radical challenge to the most fundamental laws of biology, so it’s not unreasonable to be concerned that it might threaten human society and dignity. Yet much of the ethical opposition seems also to grow out of an unthinking disgust—a sort of "yuk factor. " And that makes it hard for even trained scientist sand ethicists to see the matter clearly. While human cloning might not offer great benefits to humanity, no one has yet made a persuasive case that it would do any real harm, either.
Theologians contend that to clone a human would violate human dignity. That would surely be true if a cloned individual were treated as a lesser being, with fewer rights or lower stature. But why suppose that cloned person wouldn’t share the same rights and dignity as the rest