小明把半径为1的光盘、直尺和三角尺形状的纸片按如图所示放置于桌面上，此时，光盘与AB，CD分别相切于点N，M．现从如图所示的位置开始，将光盘在直尺边上沿着CD向右滚动到再次与AB相切时，光盘的圆心经过的距离是 ____
阅读材料，然后从各小题所给的四个选项中选出一个最佳答案。
Found:
Is this your book? Please call John at 495-3456.
Lost:
My school ID card.
My name is Mike.
Please call 487-2349
Found: Is that your black schoolbag? Please call Mary. Phone#476-5939
Found: A set of keys. Please call Lily at 498-2456
Lost: My pencil case.
Blue and white, call Tom at 456-8700.
Found: A cat. Black and White. At the school gate.
Call: 412-9856.
