The potable water system is used to store and deliver fresh drinking water.
答案解析
解析：
选项A说饮用水系统的作用是存储并向乘客发送饮用水。这个选项描述了饮用水系统的作用，但是没有提到传送新鲜的饮用水，所以不太准确。
选项B说饮用水系统必须保留并将水传送到厕所用于清洗。这个选项描述的是饮用水系统的作用，但是不准确，因为饮用水系统的作用是存储和传送新鲜的饮用水，而不是用于厕所清洗。
选项C说饮用水系统的目的是存储和传送饮用水。这个选项描述了饮用水系统的作用，而且也准确地表达了题干中的意思，所以选项C是正确答案。
所以，答案是C。饮用水系统的作用是存储和传送饮用水。
举个生动有趣的例子来帮助理解，就好比我们家里的饮水机一样，它的作用就是存储和传送饮用水，我们可以随时打开水龙头取用新鲜的饮用水。这样你就能更好地理解饮用水系统的作用了吧！
相关知识点：
饮用水系统储送饮用水
相关题目
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