图示双跨刚架各构件刚度相同，正确的弯矩图是:

• A.<img src="https://timg.fentiku.com/97/2016/12/22/xCMK2Ct8DH.png" title='xCMK2Ct8DH.png' alt='xCMK2Ct8DH.png'/>
• B.<img src="https://timg.fentiku.com/97/2016/12/22/DCVPE2LP2M.png" title='DCVPE2LP2M.png' alt='DCVPE2LP2M.png'/>
• C.<img src="https://timg.fentiku.com/97/2016/12/22/QPbubTFa0M.png" title='QPbubTFa0M.png' alt='QPbubTFa0M.png'/>
• D.<img src="https://timg.fentiku.com/97/2016/12/22/pOvPNPgh2U.png" title='pOvPNPgh2U.png' alt='pOvPNPgh2U.png'/>

正确答案：A