If the Upper and Lower Control Limits Are Set At \pm

Multiple Choice

If the upper and lower control limits are set at $\pm$ 3 standard deviations from the mean, we would expect that

A) 99.7% of the sample means are within the control limits
B) 95% of the sample means are within the control limits
C) about 68% of the sample means are within the control limits
D) about 5% of the sample means are outside the control limits