i came here by taxi and the driver charged me 50 Yuan.

答案是D.
should have done 表示“本应该”
句子表示：被宰50元,真的吗?你本应该坐公交车来.
could have done 表示“应该能”,例如：
If you had worked harder,you could have passed the exam.
（如果你（当初）再努力一点,你应该能通过考试.）
此外,
would have done 表示“应该会”,比could have done语气更肯定.
might have done 表示“也许能”,比could have done 语气更弱.
【楼主,“百度文库”和“新浪教育”都有标准答案.】Why didn’t you tell me there was no meeting today? I ________ all the way here _为什么这里选择的是needn't have driven,shouldn't have driven为什么不能选，我本来不应该坐车来的，可我却坐车来了，I shouldn't have driven ... 是“我本不应该开车来”，隐含意思是“我本可以换别的工具或方式来”。I needn't have driven ...是“我不必要开车来”，隐含意思是“我根本就不该来”（因为没有会议！）。could have done 表示“应该能”也表示有件事可以做，却没有做，should have done 不是应该表示成“本应该”不是表示命令，或者义务之类比较强硬的说法吗？could have done 表示“应该有能力”比如，“因为懒惰，我没能完成作业”，“假设我不懒，我应该能完成作业了”，英语表达是：If I hadn't been lazy, I could have finished my homework.should have done 能表示命令、义务之类的说法，比较不客气。如果是"我"作主语，即 I should have done，就没有命令的意思，而是表示自责。