[单选题]设集合A={1，2，3}，B={a，b，c}，R和S是集合A到B的关系，定义如下：R={<1,a>,<2,a>,<3,c>}，S={<1,b>,<2,a>,<3,b>}，计算 R-S=（ ）。
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2023-11-01 15:11:15|
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[单选题]设集合A={1，2，3}，B={a，b，c}，R和S是集合A到B的关系，定义如下：R={<1,a>,<2,a>,<3,c>}，S={<1,b>,<2,a>,<3,b>}，计算 R-S=（ ）。
A.{<1,a>,<2,a>,<3,c>,<1,b>,<3,b>}
B.{<1,b>,<3,b>}
C.{<1,a>,<3,c>}
D.{<1,a>,<3,c>,<1,b>,<3,b>}
A.{<1,a>,<2,a>,<3,c>,<1,b>,<3,b>}
B.{<1,b>,<3,b>}
C.{<1,a>,<3,c>}
D.{<1,a>,<3,c>,<1,b>,<3,b>}
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