Suppose N is a whole number.  If N satisfies that $\dfrac{N}{10}+\dfrac{N}{15}$~is also an integer, how many such N\textquotesingle s are there within 100? 
选项为:A:$$3$$  B:$$6$$  C:$$12$$  D:$$16$$  E:$$20$$  请回答其中一个选项.