阅读课文《自相矛盾》，回答问题。

       楚人有鬻盾与矛者，誉之曰：“吾盾之坚，物莫能陷也。”又誉其矛曰：“吾矛之利，於物无不陷也。”或曰：“以子之矛，陷子之盾，何如？”其人弗能应也。夫不可陷之盾与无不陷之矛，不可同世而立。

写出这则寓言故事的寓意。

阅读下面短文，然后从所给的四个选项中选出一个最佳答案。

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