Question

consider a circular region of a plane. if there is a changing electric field perpendicular to that plane, what can you say about any magnetic field in the circular region of the plane?
the magnetic field in the plane will exist in the form of closed concentric loops in the circular region.
the magnetic field will be perpendicular to the plane.
there will be no magnetic field.
nothing. an electric field says nothing about a magnetic field.

Explanation:

According to Maxwell's equations, a changing electric field induces a magnetic field. The induced magnetic field forms closed concentric loops around the region where the electric field is changing. This is similar to how a current - carrying wire produces a magnetic field in the form of concentric circles around the wire. In this case, the changing electric field acts as a source for the magnetic field.
The magnetic field cannot be perpendicular to the plane (as the changing electric field is perpendicular to the plane, and the induced magnetic field is in the plane according to the right - hand rule and Maxwell's equations). There will be a magnetic field (contradicting the "no magnetic field" option) and an electric field (when it is changing) does say something about the magnetic field (contradicting the "nothing" option).

Answer:

The magnetic field in the plane will exist in the form of closed concentric loops in the circular region.