给定关系R（U，Fr），其中，属性集U={A，B，C，D}，函数依赖集Fr={A→BC，B→D}；关系S（U，Fs），其中，属性集U={ACE}，函数依赖集Fs={A→C，C→E}。R和S的主键分别为（ ）。关于Fr和Fs的叙述，正确的是（ ）。
问题1选项
A.A、A
B.AB、A
C.A、AC
D.AB、AC
问题2选项
A.Fr蕴含A→B、A→C，但Fr不存在传递依赖
B.Fs蕴含A→E，Fs存在传递依赖，但Fr不存在传递依赖
C.Fr、Fs分别蕴含A→D，A→E，故Fr、Fs都存在传递依赖
D.Fr蕴含A→D，Fr存在传递依赖，但是Fs不存在传递依赖
正确答案及解析
正确答案
解析
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