An infinite cylindrical rod has a uniform volume charge density rho (where rho>0). The cross section of the rod has radius r0. Find the magnitude of the electric field E at a distance r from the axis of the rod. Assume that r Considering the symmetry of the charge distribution, choose one of the following options as the most appropriate choice of Gaussian surface to use in this problem.

a. A finite closed cylinder whose axis coincides with the axis of the rod and whose cross section has radius r0
b. A finite closed cylinder whose axis coincides with the axis of the rod and whose cross section has radius r1 c. A sphere of radius r d. A finite closed cylinder whose axis coincides with the axis of the rod and whose cross section has radius r e. An infinite cylinder whose axis coincides with the axis of the rod and whose cross section has radius r