Final answer:
The Fishbone diagram, also called an Ishikawa diagram, is the correct answer because it shows hierarchical decomposition of risk categories, unlike pie graphs which show divisions of a whole. Option A
Step-by-step explanation:
The correct answer to the student's question is A) Fishbone diagram. A fishbone diagram, also known as an Ishikawa diagram, is used for hierarchical decomposition of risk categories.
While pie graphs are effective for showing the division of an overall group into parts, with a circle representing the group as a whole and slices showing the relative sizes of subgroups, they do not show a hierarchical decomposition.
This is why a fishbone diagram is the proper choice to visually represent risk categories and break them down into their contributing factors. Option A