At my daughter's school, there is an exercise in general knowledge; this term's is about " The World Wars". The question posed is which abbreviation is correct, the first with Roman numerals or the second with Arabic numerals. Later, all questions use the second. I suspect the teacher is laying a trap so I want to be prepared.
While studying history. I was taught the former was correct;checking the Chicago Manual of Style, both are correct but only one choice should be used in a text. Have you all any guidance to offer? Oh, one other thing: I'm American trained but we live in Australia and the school reckons it is quite posh, in a British way.