There are $15$ apples in each of $6$ trees. Five children want to pick some apples. Two of them pick $13$ apples, and three of them pick $20$ apples. How many apples are left in the trees? 
选项为:A:$$4$$  B:$$6$$  C:$$8$$  D:$$12$$  E:$$15$$  请回答其中一个选项.