1. Inside a circle described by a point charge at its center will not be uniform field as a point charge field will change with distance where as we move away the field strength will go down.
2. between parallel plates of equal charge and equal magnitude will have zero electric field because both plates are of same charge so electric field of both plates will cancel each other.
3. inside a circle described by identical, evenly-spaced point charges around the circumference field will be zero as all charges are distributed uniformly and they cancel the field effect of each other.
4. between parallel plates of equal charge and opposite magnitude field will be nearly uniform as the two charges are opposite in nature and equal in magnitude so the effect will be added.
So answer of the above will be between parallel plates of equal charge and opposite magnitude
