A ball is thrown from the top of a building and each time the ball bounces to half of its previous height. If the height of the building is $$512$$ meters, which time does it bounce when it bounces to a height of $$16$$ meters? 
选项为:A:$$4^{th}$$  B:$$7^{th}$$  C:$$6^{th}$$  D:$$8^{th}$$  E:$$5^{th}$$  请回答其中一个选项.