Answer:
which class??????????????????
The answer is D. The Civil war and World war 1
I want to go to the concert, but I'm not sure if I will be able to make it.
This one uses correct comma usage to join two independent clauses, the comma goes before the coordinating conjunction (but).
The semicolon would only be used before the coordinating conjunction if in the first clause a comma was used. But that's not the case so the answer with the semicolon is thus incorrect.
An interlude can really take on any emotion that you wish for it, but if you have to choose between one of these option then I suppose the best is "somber"