Hi Vickey Kumar.

With a rank of 5900 and BC category reservation, you can get admission in government colleges. some of them are - 

DCE Darbhanga - CSE

MIT Muzaffarpur - LT

NCE Chandi - CSE

MCE Motihari - CSE

LJPIT Chapra - CSE

BPMCE Madhepura - ME, EEE

KCE Katihar - ME

etc. these are the top colleges and courses you can get. For the complete list, please use the college predictor tool.

https://engineering.careers360.com/bcece-college-predictor

Good Luck.