图示杆的重量为P,放置在直角槽内。杆与槽为光滑面接触,A、B、C为三个接触点,则该杆的正确受力图是( )

A、<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/16068971005350376127d7f434aab8a3321128ee25746.png">

B、<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/16068971140589d9852d2707d45d1a96785181cc40c8d.png">

C、<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/1606897125838d6daeb771fd2436c9bcc32f31bc550e0.png">

D、<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/16068971368120a64aff5b0714ef19b72ac6d75daa59f.png">