图示桁架的所有杆件EA值均相同，则桁架A点的竖向位移最小的是()。

• A.<img src="https://timg.fentiku.com/img/2018-04-09/5acad74ad858d.png" alt="" />
• B.<img src="https://timg.fentiku.com/img/2018-04-09/5acad74b08576.png" alt="" />
• C.<img src="https://timg.fentiku.com/img/2018-04-09/5acad74b26dc5.png" alt="" />
• D.<img src="https://timg.fentiku.com/img/2018-04-09/5acad74b465b4.png" alt="" />

正确答案：D