Aregion contains a volume charge density p = a .ifelectric flux through a sphere of radius r centred at origin is .then electric flux through concen- tric spher

Aregion contains a volume charge density p = a .Ifelectric flux through a sphere of radius R centred at origin is .Then electric flux through concen- tric sphere of radius 2R is (a) o (b) 80% (c) 32% (d) 64%