Answer: a. Pareto
Explanation:
A Pareto Chart is a graph that indicates the frequency of defects, as well as their cumulative impact. Pareto Charts are useful to find the defects to prioritize in order to observe the greatest overall improvement.
Fishbone diagram or Ishikawa diagram is a cause-and-effect diagram that helps managers to track down the reasons for imperfections, variations, defects, or failures.
Ordered Histogram is an approximate representation of the distribution of numerical data.
A histogram is a bar graph that illustrates the frequency of an event occurring using the height of the bar as an indicator.