The Quality Assurance Department selected a sample of 12 printed circuit boards and tested them. The number of defects in each circuit board was 3, 3, 0, 5, 1, 1, 5, 6, 6, 2, 0, and 1. What kind of control chart should be constructed to monitor the process? A. Mean chart B. Range chart C. Percent defective chart D. C-bar chart

To determine which control chart should be constructed to monitor the process, we need to analyze the data provided.

Typically, control charts are used to monitor and control a process by showing how a process variable changes over time. There are several types of control charts available, but the choice depends on the type of data and the specific objective of the analysis.

In this case, we are given data points representing the number of defects in each printed circuit board. This data follows a count-type variable, which means we need to use a control chart designed for count data.

The appropriate control chart for count data is the "C-chart" or "C-bar chart." The C-chart is used to monitor the number of defects per unit of a process or product. It is suitable when the sample size (number of circuit boards in this case) varies.

Therefore, the correct answer is D. C-bar chart.