Statistical Inference — identifying the UMP test from its critical region

Let $x_1, x_2, x_3, …, x_n$ be a random sample from $N(0, \sigma^2)$, $\sigma > 0$. Which one of the following hypotheses has the critical region $\sum_{i=1}^{n} x_i^2 \ge 2\chi^2_{(n,\alpha)}$ as the UMP critical region of level $\alpha$, where $P(\chi^2_{(n)} > \chi^2_{(n,\alpha)}) = \alpha$?