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You mean like when you choose to visit Point B and then Point C becomes Permanently Missable Content?
Using a map interface to choose your route might be Point-and-Click Map.
If a certain area becomes permanently missable as a result, it would be Permanently Missable Content.
Story Branching has an image of that, but this is more related to what comes up rather than simply choosing an option in a linear route (that doesn't affect the story).

In a map, there will be two points from Point A (Point B or Point C) and you have to choose which on to go. If you choose one, you can't go to the other anymore.
I know there's a trope for this but I can't place the name.