3. Let and be two distinct sets.
Proposition ;
Proposition or .
Then is a ( ) condition for .
(A) Sufficient and necessary
(B) Sufficient but not necessary
(C) Necessary but not sufficient
(D) Neither sufficient nor necessary
3. Let and be two distinct sets.
Proposition ;
Proposition or .
Then is a ( ) condition for .
(A) Sufficient and necessary
(B) Sufficient but not necessary
(C) Necessary but not sufficient
(D) Neither sufficient nor necessary
3. B.
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