Users typically forget to add components when they create new issues. As a result, most of the newly created issues get

[answerhappygod]

Users typically forget to add components when they create new issues. As a result, most of the newly created issues get assigned to Tom, who is the project lead.
Tom reviews all of the issues, and wants to triage them based on component selection. But when he edits an issue and adds a component, the assignee does not change.
Why does the assignee not change when adding a component to an issue?

A. Auto-assignment with components only works when creating issues.
B. The project's default assignee overwrites the value of the component lead.
C. The default assignee of the selected components is set to Project default.
D. The Assignee field additionally needs to be changed to Automatic.
E. The selected components do not have a component lead set.