A、Pessimistic. B、Optimistic. C、Radical. D、Practical. B由最后一句话可得知作者对疼痛的态度是乐观的：... although pain is an unpleasant sensation, it is

A moment’s drilling by the dentist may make us nervous and upset. Many of us cannot stand Pain. To avoid the pain of a drilling that may perhaps last a minute or two, we demand some medicine that deadens the nerves around the tooth.
    Now it’s true that the human body has developed its millions of nerves to be highly aware of what goes on both inside and outside of it. This helps us adjust to the world. Without our nerves and our brain, which is a group of nerves we wouldn’t know what’s happening. But we pay for our sensitivity. We can feel pain when the slightest thing is wrong with any part of our body. The history of torture is based on the human body being open to pain.
    But there is a way to handle pain. The big thing in withstanding pain is our attitude towards it. If the dentist says, "This will hurt a little," it helps us to accept the pain. By staying relaxed, and by treating the pain as an interesting sensation, we can handle the pain without falling apart. After all, although pain is an unpleasant sensation, it is still a sensation, and sensations are the stuff of life.