For a spherically symmetrical charge distribution, electric field at a distance r from the centre of sphere is `vecE=kr^7hatr`, where k is a constant. What will be the volume charge density at a distance r from the centre of sphere ?
Options:
(a) `rho= 9kepsilon_0 r^6`
(b) `rho=5kepsilon_0 r^3`
(c) `rho=3kepsilon_0 r^4`
(d) `rho=9kepsilon_0 r^0`