Read the following three passages．Each passage is followed by several questions or unfinished statements．For each of them there are four choices marked A, B, C and D．Choose the one that fits best according to the information given in the passage you have just read．

　　A 63-year-old man who hasn't slept for more than two decades has been told there is nothing wrong with him by doctors．

　　Ukrainian Fyodor Nesterchuk from the town of Kamen-Kashirsky said the last time he managed to sleep was more than two decades ago．

　　"I can't remember the exact date and I don't know why it started, but all of a sudden I found it more and more difficult to nod off until eventually I was awake the entire night．I used to read boring scientific magazines in the hope that they would send me to sleep．But as soon as I felt my eyes getting closed and put the magazine down, I would find myself wide awake again．I thought it would just be a period of time but it has gone on for over two decades now and I've simply had to get used to it．Now when everyone else sleeps I get stuck into a good book," said Nesterchuk．

　　All attempts by doctors to put him to sleep have failed．Local doctor Fyodor Koshel who has examined Nesterchuk extensively and has been unable to make him fall asleep, said he has no idea of the cause of the insomnia and added medically there is nothing wrong with him．"We have no idea why he can't sleep, maybe it's the result of a past illness．But in terms of medical science, he's not in any pain and so there isn't anything actually wrong with him," said Dr Koshel．