The numbers $4$, $5$, $6$, $7$ and $8$ are divided into groups of one or more numbers. The sum of the numbers in each group is the same. Which number must be in the group with the number $8$? 
选项为:A:$$4$$  B:$$5$$  C:$$6$$  D:$$7$$  E:Not sure.  请回答其中一个选项.