What's the deal with Yeomen?

I'm watching TOS all the way through for the first time (had seen scattered episodes and the movies before) and one of the things that struck me/confused me coming from a TNG/VOY/DS9 perspective is the role of Yeoman Rand.

From Memory Alpha and from context in the episodes, it appears that the Yeoman's role is to help the captain with administrative matters, essentially like a secretary or personal assistant.

My question is, why did the use of Yeomen apparently fall out of favor after the TOS era? If anything, it seems like having someone in that role would be even more important given how much larger and more complicated bigger starships would be. A few potential explanations I thought of:

(A) Yeomen do exist but we just don't see them on screen because their role is limited to mundane tasks. This explanation is a little bit undermined by TOS since Yeoman Rand accompanies Kirk on many away missions and is usually by his side on the bridge. If other captains had a Yeoman, wouldn't they have been similarly omnipresent?

(B) The tasks that Yeomen used to perform in TOS are automated by the time we get to TNG. This is certainly possible, though it seems like Starfleet generally prefers to avoid automation (or just use it as a backup) where possible given other things we see that aren't automated on the show (ex. the barber).

(C) Yeomen exist, but the captains we see in all the series after TOS prefer not to use one. I think this is a feasible explanation when it comes to Janeway or Sisko because of their more hands on personalities (or in Janeway's case, perhaps lack of available personnel). But Picard seems like more of a delegator who prefers to focus on the "big picture" (plus, with the size and civilian element of his ship, it seems the most complex to run).

(D) Yeomen no longer exist for some other reason.

Thoughts?