The type of sentence given is a compound sentence. It is a compound sentence because it consists of two independent sentences: "I already said yes to someone else" and "I can't go to the dance with you". In order to link the two sentences, the conjunction "because" is used.
I believe that would come to 704ft/min
D. their.
the're isn't a word, they're means they are, and there means something is over there. Their means that it is THEIR coat, THEIR pencil. hope i helped :)