[单选题]变电站内移运铁管时严禁高举，严格保持与带电部位的（　　）。
A.最大距离
B.最小距离
C.有效距离
D.安全距离

{{B}} Questions 47 to 56 are based on the following passage.{{/B}}
The Olympic games (often referred to simply as The Olympics or The Games) is an international multi-sport event subdivided into summer and winter sporting events. The {{U}} (47) {{/U}}Olympic Games began in 776 BC in Olympia, Greece, and was celebrated until AD 393. There are many myths and {{U}} (48) {{/U}} of the origin of the ancient Olympic Games. The most popular one describes that Hercules was the creator of the Olympic Games, and built the Olympic stadium and surrounding buildings to {{U}} (49) {{/U}} his father Zeus. The date of the Olympic Games’ beginning based on the count years in Olympiads is reconstructed as 776 BC, although scholars’ opinions differ between dates as early as 884 BC and as late as 704 BC. From then on, the games became much more important throughout ancient Greece, {{U}} (50) {{/U}} their peak in the sixth and seventh century BC.
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