Statistical Inference — properties of a single observation from N(0,theta)

Let $x_1,x_2,…,x_n$ be a random sample from Normal distribution $N(0,\theta)$, $\theta\ge0$. Consider the following statements in respect of $x_1$: 1. $x_1$ is unbiased for $\theta$. 2. $x_1$ is complete statistic for $\theta$. 3. $x_1$ is sufficient for $\theta$. How many of the above statements are correct?