In the con of a uniform charged sphere, given rho₀ = q / (4/3 π r³), express the density rho₀ in terms of the total charge q on the sphere.
a) rho₀ = 3q / (4πr³)
b) rho₀ = q / (πr³)
c) rho₀ = 4q / (3πr³)
d) rho₀ = q / (3πr³)