Suppose an estimator $\hat{\theta}_n$ for a parameter $\theta$ is based on $n$ samples and satisfies $\sqrt{n}(\hat{\theta}_n - \theta) \xrightarrow{d} N(0, V(\theta))$. If we are interested in the asymptotic distribution of the transformation $g(\theta) = \theta^k$ for $\theta > 0$, what does the Delta Method specify as the asymptotic variance of $\sqrt{n}(g(\hat{\theta}_n) - g(\theta))$?