Answer:
the right answer is option C.
Explanation:
in option A. it does not start with an upper case. thus it is not right.
in option B. there is a coma missing after 'Dance'. and also the meaning of the sentence turns out to be that he promised that he would give the gift after the dance not that he gave the gift after the dance. I guess this is not right too.
in option C. I don't find any mistake
