Which settings menu lets someone find one option faster?

Version B works better here. Faced with the flat list, you read down twelve unsorted options, holding the whole list in your head until you spot the one you want. Grouped, you make two small decisions instead: glance at three or four headings, pick “Notifications”, then choose from the two items under it.

That is Hick's law: the time to decide grows with the number and complexity of the choices on offer. Grouping does not remove options, it stages them - so each step is a small, fast decision rather than one long scan.

The honest caveat: grouping only helps when the labels are ones people actually expect. Good categories speed everything up; arbitrary ones just add a layer to dig through. The judgement is in the grouping, not the act of grouping itself.