Can "therefore" be used as a conjunction?

[on the way]

Hi, everyone.
First please look at the following question.
___ Sunday, therefore the game was called off.
A. It being B. It was C. Being D. So it was
According to where the question comes from, the key to this question opts for B, which would suggest at least to me that "therefore" can also be used as a conjunction. But I'm not quite sure about that, so here I am, hoping to get some confirmation or refutation. Any response is appreciated. Thank you all again.

 

[5jj]

B is the only possible answer, but the resulting sentence is not good English. 'Therefore' does not function as a conjunction.

 

[on the way]

QUOTE=5jj;968935c]B is the only possible answer, but the resulting sentence is not good English. 'Therefore' does not function as a conjunction.[/QUOTE]
According to what I have been taught,only a conjunction of sort can join two sentences or clauses.Can an adverb like "therefore" also function as such?