Answer:
The correct answer is: a c-chart.
Step-by-step explanation:
Graph c is used when a piece of the product may have a different number of defects per piece, in this case what we are interested in controlling is the number of defects per piece.
Graph C serves to control the production process, by knowing the number of defects that appear in a sample.
This graphic is used when the quantity of products produced is very low or in physically large products such as machinery.