Identify the Appropriate Control Chart for Attributes Data

Identify the appropriate control chart for attributes data.
-A manufacturer of a particular grade of copper tubing collects data on the number of
Flaws occurring in 500 foot coils. Suppose they sample a total of 40 coils to initiate
Control charting. The average number of defects per coil is 2.5. The appropriate control
Chart for these data is the

A) R chart.
B) c chart.
C) x-bar and R chart.
D) p chart.
E) ARL chart.