两条平行直线 <img src="https://static.zxtiku.com/wangke/imgs/topic/ae73854008109b2bc17c73d6f3d8be76.jpg"/><img src="https://static.zxtiku.com/wangke/imgs/topic/a7a05a7a6d5724c2fe9f61fa6d377f20.jpg"/> 的距离是( ). A. √2 B. <br/> 2/3√3 C. <br/> 2/3 D. <br/> 2