2. If $a, b, c$ are three arbitrary integers, then, $\frac{a+b}{2}$, $\frac{b+c}{2}, \frac{c+a}{2}(\quad)$.
(A) None of them are integers
(B) At least two of them are integers
(C) At least one of them is an integer
(D) All of them are integers
2. C

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