dear Aniket,

always use the Documents of that state of which you have Domicile.

if you attach you SC Certificate,then you will be provided home quota for Bihar at the time of councelling.

but one more thing,there is a few scope in engineering in Bihar.

never use documents of two different states.

for more information you can use the given link

          nta.ac.in

I hope you understand

thank you.