Ron\textquotesingle s work day is half over at $$1:15$$ P.M. if he starts work at $$9:30$$ A.M., his work day ends at． 
选项为:A:$$4:30$$ P.M.  B:$$5:00$$ P.M.  C:$$5:30$$ P.M.  D:$$9:30$$ P.M.  请回答其中一个选项.