单选题：已知P是r的充分条件而不是必要条件，q是r的充分条件，s是r的必要条件，q是s的必要条件，现有下列命题：①s是q的充要条

题目内容：
已知P是r的充分条件而不是必要条件，q是r的充分条件，s是r的必要条件，q是s的必要条件，现有下列命题：①s是q的充要条件；②P是q的充分条件而不是必要条件；③r是q的必要条件而不是充分条件；④乛P是乛s的必要条件而不是充分条件；⑤r是s的充分条件而不是必要条件。
则正确命题的序号是（　　）。 A．①④⑤
B．①②④
C．②③⑤
D．②④⑤

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