If a sample of items is taken and the mean of the sample is outside the control limits$,$ the process is:

A$.$ monitored closely to see if the next sample mean will also fall outside the control limits$.$

B$.$ in control, but not capable of producing within the established control limits$.$

C$.$ likely out of control and the cause should be investigated.

D$.$ within the established control limits with only natural causes of variation.

E$.$ producing high quality products.