P and Q true →p or Q true, 1 right.

2, p and q are false, then at least one of p and q is false. When both are false, P or Q is false and 2 is wrong.

3, non-P is false, P is true, so P or Q is true, after → before, not necessary, 3 pairs.

4, P and Q are false, then at least one of P and Q is false, Q is false, when P is true, non-P is false and 4 is wrong.

Choose B.

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