For the Formula for Calculating the Confidence Level with Known $\sigma / \sqrt{n}$

Multiple Choice

For the formula for calculating the confidence level with known standard deviation, the value ________ represents the value of a standard normal random variable with a cumulative probability of 1 - α / 2.

A) $\sigma / \sqrt{n}$

B) $z_{a / 2}$

C) $\bar{x}$

D) $x_{i}-\bar{x}$