Electrostatics

The potential (in volts) of a charge distribution is given by. V(z) = 30 $-$ 5x² for $\left| z \right|$ $\le$ 1 m. V(z) = 35 $-$ 10 $\left| z \right|$ for $\left| z \right|$ $\ge$1 m. V(z) does not depend on x and y. If this potential is generated by a constant charge per unit volume ${\rho _0}$ (in units of ${\varepsilon _0}$) which is spread over a certain region, then choose the correct statement.