A)(overline(X) - u_(alpha) (2)/(sqrt(n)), overline(X) + u_(alpha) (2)/(sqrt(n)) ) B)(overline(X) - u_((alpha)/(2)) (4)/(sqrt(n)), overline(X) + u_((alpha)/(2)) (4)/(sqrt(n)) ) C)(overline(X) - u_(alpha) (4)/(sqrt(n)), overline(X) + u_(alpha) (4)/(sqrt(n)) ) D)(overline(X) - u_((alpha)/(2)) (2)/(sqrt(n)), overline(X) + u_((alpha)/(2)) (2)/(sqrt(n)) )

设总体 $X \sim N(\mu, 4)$，$(X_1, X_2, \cdots; X_n)$ 是总体 $X$ 的样本，令 $\overline{X} = \frac{1}{n} \sum_{i=1}^n X_i$，则 $\mu$ 的置信水平为 $1 - \alpha$ 的置信区间为().

A)$\left(\overline{X} - u_{\alpha} \frac{2}{\sqrt{n}}, \overline{X} + u_{\alpha} \frac{2}{\sqrt{n}} \right)$

B)$\left(\overline{X} - u_{\frac{\alpha}{2}} \frac{4}{\sqrt{n}}, \overline{X} + u_{\frac{\alpha}{2}} \frac{4}{\sqrt{n}} \right)$

C)$\left(\overline{X} - u_{\alpha} \frac{4}{\sqrt{n}}, \overline{X} + u_{\alpha} \frac{4}{\sqrt{n}} \right)$

D)$\left(\overline{X} - u_{\frac{\alpha}{2}} \frac{2}{\sqrt{n}}, \overline{X} + u_{\frac{\alpha}{2}} \frac{2}{\sqrt{n}} \right)$