Cassandra is helping her mother to pack $$75$$ cupcakes. The boxes that her mother prepares can only fit $$7$$ cupcakes. She must ensure the box is full before she can use the next box. How many boxes she can fill up? 
选项为:A:$$1$$  B:$$5$$  C:$$10$$  D:$$68$$  E:$$70$$  请回答其中一个选项.