如图所示，图（b）为图（a）所示结构的力法基本体系，EI=常数，则在力法方程δ11X1+δ12X2+Δ1P=0中（）。<img src="https://static.zxtiku.com/wangke/imgs/topic/7a01dd04e8f668f20e156bcfebb69dc9.jpg"/><br/> A、<img src="https://static.zxtiku.com/wangke/imgs/topic/9e60fdba294bb7565bc7c321320305c4.jpg"/><br/> B、<img src="https://static.zxtiku.com/wangke/imgs/topic/a5b68cbfb79e0aca26cf5744dfe447cb.jpg"/><br/> C、<img src="https://static.zxtiku.com/wangke/imgs/topic/b9e570a098956b947a40240d963c0f86.jpg"/><br/> D、<img src="https://static.zxtiku.com/wangke/imgs/topic/c3728cb3dcb030c2808963950d3ebda4.jpg"/>