I ate half an apple pie on Saturday and two thirds of the remainder on Sunday. What fraction of the pie was left for Monday?　 
选项为:A:None　  B:$$\frac{1}{2}$$  C:$$\frac{1}{3}$$  D:$$\frac{2}{3}$$  E:$$\frac{1}{6}$$  请回答其中一个选项.