If you have already tried linking to “Biography A” from a few different places in your manuscript, try going to that biography in the main editor, and use the Navigate ▸ Inspect ▸ Bookmarks menu command or shortcut. If the inspector panel that opens up says “Project Bookmarks” at the top, click it and switch to Document Bookmarks.
Every time you make a link (or bookmark, as you have ultimate control over this list) between things, a backlink gets stashed here. It’s extremely useful! I share some tips on how this capability can be used in this longer guide on more advanced linking techniques in Scrivener. The use case I give is for better large-scale revision tracking, but the core concept works for everything, including this.