Multiple Category URL

Hello there 🙂

Quick question: what’s the basis for WP choosing what category is displayed in the URL? For example, if you have a certain post placed in three different categories, why does it choose one category over another to display it in?

I have a site that has “Blog”, “Tools” and “Callout” categories. If I place a single post in all three categories, the permalink URL will change to “callout/postname” every time. However, I want it to have “blog/postname”. How do I make it so the category I want is the one that it shows up in?