A Sankey diagram is the most appropriate visualization for this requirement. It is specifically designed to illustrate the flow and magnitude of transitions between different states or stages. In this scenario, it can effectively map the journey of students, showing how the distribution of majors changes from one grade level (e.g., Freshman) to the next (e.g., Sophomore). The width of the connecting paths (links) between the nodes (majors) would be proportional to the number of students, clearly visualizing the paths, including where students remain in the same major and where they switch.

A. Chord Chart: A chord chart is used to visualize relationships and flows between a single set of entities, not a sequential, multi-stage progression across different grade levels.

B. Tree Chart: A treemap is designed to display hierarchical data and part-to-whole relationships using nested rectangles. It cannot represent the flow or transition of data between categories.

C. Radar Chart: A radar chart is used for comparing multiple quantitative variables for one or more series. It is unsuitable for visualizing flow or paths between categorical states.

1. Salesforce Help Documentation

CRM Analytics Chart Types:

Sankey Diagram: "Visualizes the distribution of a measure from one grouping to another grouping. The groupings are the source and destination dimensions." This directly aligns with visualizing the distribution of students (measure) from majors in one grade level (source) to majors in the next (destination).

Reference: Salesforce Help. (2023). CRM Analytics Chart Types. Retrieved from https://help.salesforce.com/s/articleView?id=sf.bicharttypes.htm&type=5

2. Salesforce Help Documentation

Create a Sankey Diagram:

Use Case: "Use a sankey diagram to visualize the flow of data from one category to another. For example

identify how leads from different campaigns flow through the lead status." This example of tracking flow through stages (lead status) is analogous to tracking students through stages (grade levels and majors).

Reference: Salesforce Help. (2023). Create a Sankey Diagram. Retrieved from https://help.salesforce.com/s/articleView?id=sf.bicharttypesankeycreate.htm&type=5