Which of the Following Statements Is True

Multiple Choice

Which of the following statements is true?

A) For a variables control chart, n should be fairly large, frequently 50-300 observations.
B) For an attribute control chart, n is typically 5-10 observations, and rarely larger than 24.
C) For an attribute control chart, n should be large enough to include at least one defective unit.
D) None of the above.