An X-Bar Control Chart Was Examined and No Data Points

Multiple Choice

An x-bar control chart was examined and no data points fell outside of the limits. Can this process be considered in control?

A) No, there could be a pattern to the points, the R-chart must be checked.
B) Yes, it is unlikely that there is a pattern in these points.
C) No, the number of samples must be known.
D) Yes.
E) Yes, there is not enough data to determine otherwise.