If a Sample of Parts Is Measured and the Mean

If a sample of parts is measured and the mean of the measurements is outside the control limits, the process is:

A) in control, but not capable of producing within the established control limits.
B) out of control and the process should be investigated for assignable variation.
C) within the established control limits with only natural causes of variation.
D) monitored closely to see if the next sample mean will also fall outside the control limits.
E) none of the above.