[单项选择]依据《特种作业人员安全技术培训考核管理规定》规定，特种作业人员在特种作业操作证有效期内，连续从事本工种（）年以上，并符合相关规定，特种作业操作证的复审时间可以延长至每6年1次。
A. 5
B. 10
C. 15
D. 20

Cities can be frightened places. The majority of the population live in noisy massive tower blocks. The sense of belonging to a community tends to appear when you live thirty floors up in a skyscraper. Strange enough, whereas in the past the inhabitants of one street all knew each other, nowadays people on the same floor in high buildings even say hello to each other.
Country life, on the other hand, differs from this kind of isolated existence in that a sense of community generally keep the inhabitants of small villages together. People have the advantage of knowing that there is always someone to turn to when they need help. So country life has disadvantages too. For example, shopping becomes a major problem, and for anything slightly out of the ordinary you have to go for an expedition to the nearest large town. The country has the advantage of peace and quiet, but suffers with the disadvantage of being cut off. The ci