To answer this question, the user needs to be familiar with graphical tools used in process improvement.

Option A, ANOVA, is a statistical test used to analyze the difference between the means of two or more groups. ANOVA is not a graphical tool used for identifying opportunities for improvement, so it is not the correct answer.

Option B, Cost/benefit analysis, is a financial tool used to compare the costs of a project or decision to its potential benefits. While cost/benefit analysis can be useful for evaluating the feasibility of improvement opportunities, it is not a graphical tool. Therefore, it is not the correct answer.

Option C, Pareto Analysis, is a graphical tool used to identify the most significant sources of a problem or issue. The Pareto chart is used to show the frequency or volume of each source, allowing the user to prioritize which sources to address first. Pareto Analysis is a common tool used in process improvement, and it is the correct answer.

Option D, Control Charts, are graphical tools used to monitor the performance of a process over time. Control charts help identify when a process is out of control and may require corrective action. While control charts can be useful for identifying opportunities for improvement, they are not primarily used for that purpose. Therefore, option D is not the correct answer.

The Answer is: C. Pareto Analysis