孙明去看一部不足一小时的纪录片。刚开演时他看了一下表，结束时他再看表的时候，时针与分针正好交换了位置。则这部片子时长为（　　）分钟。

A、50

B、52<img width="19" height="37" src="http://admintk.100xuexi.com/UpLoadImage/2016-08-23/94c178e3-1c19-420c-84ee-da1ebc7beb20.png" />

C、53

D、55<img width="19" height="37" src="http://admintk.100xuexi.com/UpLoadImage/2016-08-23/94c178e3-1c19-420c-84ee-da1ebc7beb20.png" />

B、52<img width="19" height="37" src="http://admintk.100xuexi.com/UpLoadImage/2016-08-19/2d418152-9c83-44a1-85ec-64f039722a9c.png" />

D、55<img width="19" height="37" src="http://admintk.100xuexi.com/UpLoadImage/2016-08-19/2d418152-9c83-44a1-85ec-64f039722a9c.png" />