Which of the following tools would a project manager use to determine the root cause of an issue?

A Pareto Chart ranks defects or issues by frequency or cost to apply the 80/20 rule and prioritize which problems to address first - it identifies what to fix, not why it occurred.

The Ishikawa diagram, also called the fishbone or cause-and-effect diagram, organizes potential causes of a problem into categories (such as people, process, equipment, and environment) branching off a central 'spine.' It is the standard tool for structured root cause analysis because it visually maps the relationship between an effect and all its possible contributing causes, helping teams identify the true source of an issue.

A Histogram displays the frequency distribution of a data set over intervals, useful for understanding variation patterns but not for tracing causation.

Monte Carlo Analysis is a quantitative risk simulation technique used to model schedule or cost uncertainty through repeated random sampling - it is not a root cause analysis tool.