Let r be a rational instance with schema R = (A, B, C, D). We define r

1.	Let r be a rational instance with schema R = (A, B, C, D). We define r
A.	s r
B.	r s = r
C.	r s
D.	r * s = s
Answer» D. r * s = s

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Let r be a rational instance with schema R = (A, B, C, D). We define r

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