1. Let $x$ be a real number, $y=|x-1|+|x+1|$. Among the following four conclusions, the correct one is ( ).
(A) $y$ has no minimum value
(B) There is only one $x$ that makes $y$ take the minimum value
(C) There are infinitely many $x$ that make $y$ take the minimum value
(D) There are finitely many $x$ that make $y$ take the minimum value
(Answer: (C)).

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