"Chiếc bánh mì"
Yes, you're right. Chiếc bánh mì is widely used in the North, whereas ổ bánh mì is typically in the South.
I believe things made py people tend to get 'chiếc' - though it's certainly not a hard and fast rule!
In a previous question it gave the answer "bánh mi" (with no classifier) for "the bread" and in the comments people were saying it did not require one. This question, it needs chiêc. There are similar discrepancies for other words. This inconsistency makes the already complicated classifiers incredibly difficult to understand. Pick a rule and stick to it.
They function to aid with counting them and also differentiating between definiteness and indefiniteness. e.g.
mèo = cats (in general)
con mèo = the cat
một con mèo = a cat, one cat
hai con mèo = two cats
mấy/những con mèo = the cats
Those are great, but unfortunately unaccessible from the app versions (both android and iOS).
The classifier chiếc is used in northern Vietnam, while ổ is used in southern Vietnam
Yes, if this is a classifier lesson, then let's practice using classifiers. If the classifier for bành mì is CHIẾC, then let's have it in EVERY "The bread" question.
This is incorrect. One would say "ở bánh mì." Ở meaning loaf. Chiếc is a classifier for a car or single shoe but not bread.
The first word doesn't go with the sentence so it doesn't make sense if you translate it.