Amy calculate $47\times86$ wrong. Her teacher says her result which has a difference of $172$ from the correct one. After checking, Amy finds that she writes one of the four digits two multipliers the result as $9$. Which digits does she write incorrectly? 
选项为:A:$$4$$  B:$$7$$  C:$$8$$  D:$$6$$  E:It\textquotesingle s impossible to determine.  请回答其中一个选项.