There are two options with $$\triangle $$ and $$\bigcirc $$.  $$\bigcirc +8=13 $$  $$\triangle \times \bigcirc =15 $$.  What number does the $$\triangle$$ represent? 
选项为:A:$$5$$  B:$$4$$  C:$$3$$  D:$$6$$  E:$$7$$  请回答其中一个选项.