A semicolon continues the story. For example; I could have just stopped and said one setence but I continued on by putting a semicolon since there was more to tell.
The majority of the Diary of Anne frank's play adaption is presented in : Diary Entries
To get to safety, Winton's children had to travel through the heart of Nazi Germany. Eight trains departed from Warsaw between March and August 1939
I find all of the answers pretty neutral (that is, giving only facts, no judgements) except on sentence 3: this is because of the word "sharply".
It seems that the author of this sentence makes a judgement about the split: that they're very split, that their argument was very intense. It seems like a judgement to me more than the other sentences.
I think it would be a. formal