单选题
The management system of the rapid transit rail lines ______.
A、
is already quite developed
B、
does not exist at all
C、
is not good enough
D、
needs to include the strict guidelines
【正确答案】
C
【答案解析】
[注释] 本题需要进行推断，依据是第二段首句，关键部分是management systems of such lines should be improved，意思是“管理系统需要改进”，即还不够完善。
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