Option A, you keep discarding and drawing until you stop ditching a land, had this happen to me before and it was really weird haha
wtf? I don't think that's right in paper Magic, because it wouldn't recheck your hand. That would be the equivalent of having multiple clean-up phases.
That said, Magic Duels does things it's own way, so I don't doubt it happened to you. I just don't think it SHOULD happen to you.
EDIT: So I looked it up and apparently Duels is right. You just have infinite successive clean up phases
https://blogs.magicjudges.org/rulestips ... -twilight/There’s a lot of cards in the new and mad Innistrad that instruct you to discard cards, but perhaps the most interesting one is the one that isn’t connected to Innistrad at all: discarding down to hand size at the end of your turn (formally known as the cleanup step). So what happens if you end your turn with The Gitrog Monster and eight cards in hand, and you decide to discard a land? Normally, no one has priority during this time. However, because The Gitrog Monster had a triggered ability that triggered in the middle of the cleanup step, the ability goes on the stack, and players can play spells and abilities in response. After the ability resolves, players get another window to play spells and abilities. So, if you drew a spell with The Gitrog Monster, you’d be able to cast it during that cleanup step. Then, after all players have passed priority, the game… goes to another cleanup step. If you’ve still got eight cards in your hand at this time, you’ll have to discard one again. If the one you discarded was a land, you’ll have to draw with The Gitrog Monster, pass priority, go to another another cleanup step, discard a card from your hand, and so on and so forth until you stop drawing cards, because the game cannot progress to the next turn until an entire cleanup step goes by with no state-based actions happening and no abilities triggering.