A school has two classes in the morning, each class continues $$45$$ minutes, and there is a break between classes. The first class starts at $$10:00$$, and the second class ends at $$12:00$$. How long does the courseware rest? 
选项为:A:$$10$$  B:$$15$$  C:$$20$$  D:$$30$$  E:$$35$$  请回答其中一个选项.