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Number of equivalence relations on set {a, b, c}:
A5 (Bell number B₃: partitions of 3-element set)
B6
C3
D1
Answer & Solution
Correct answer: A. 5 (Bell number B₃: partitions of 3-element set)
Equivalence relations correspond to partitions. B₃ (Bell number) = 5. Partitions of {a,b,c}: {a,b,c}; {a,b}{c}; {a,c}{b}; {b,c}{a}; {a}{b}{c}. Total 5.
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