题目

It is often said that politeness costs nothing．In fact，it seems that a little more courtesy could save businesses￡5 billion every year． Frequently hearing the phrase “thank you” or “well done” means the same to staff as a modest pay rise，researchers say． Praise and encouragement also makes employees more likely to work hard and stay in their jobs，saving on the cost of finding replacements． A third of 1,000 workers surveyed by consulting firm White Water Strategies said they did not get thanked at all when they did well—and a further third said they were not thanked en1．五棱锥P-ABCD的体积为5，三视图如图所示，则侧棱中最长的一条的长度是（　　）A．6B．3$\sqrt{3}$C．3$\sqrt{2}$D．4$\sqrt{2}$