Which of these is a correct expression for the UCL of the modified control charts when the type I error is not specified?

• A. \(UCL=USL+\left(Z_δ+\frac{3}{\sqrt{n}}\right) \sigma \)
• B. \(UCL=USL+\left(Z_δ-\frac{3}{\sqrt{n}}\right) \sigma \)
• C. \(UCL=USL-\left(Z_δ-\frac{3}{\sqrt{n}}\right) \sigma \)
• D. \(UCL=USL-\left(Z_δ+\frac{3}{\sqrt{n}}\right) \sigma \)