下述______成立时，称 X→Y为平凡的函数依赖。
A.[img src="https://img.haodaxue.net/uploadimg/ico/2020/0610/1591776367550266.png" />
B.[img src="https://img.haodaxue.net/uploadimg/ico/2020/0610/1591776372169721.png" />
C.[img src="https://img.haodaxue.net/uploadimg/ico/2020/0610/1591776379511106.png" />
D.[img src="https://img.haodaxue.net/uploadimg/ico/2020/0610/1591776384328338.png" />
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正确答案： D 答案分析：无
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