The answer is D because it states an hypothetical situation, as you explained above.
Answer:
The correct options are:
A) Jonas has homework. It isn't finished. and
D) Jonas has homework, it isn't finished.
Explanation:
In all the correct instance, the sentence is constructed such that there are still two independent clauses.
In A above, the clauses are clearly identified and so is the point of their separation.
The same is true for D.
In B, C, and E the sentences are no longer independent.
In F, the demarcation between two sentences by the semicolon is evident however the second half of the sentence is no longer dependent as it is missing the pronoun "it".
Cheers!
