a time-dependent magnetic field is observed in a region of space. an electric field is also observed in the same region. which of the following statements must be true if the electric field created the time-dependent magnetic field? responses the electric field must be time dependent. the electric field must be time dependent. there must be a fixed-charge distribution in the region. there must be a fixed-charge distribution in the region. there must be excess positive or negative charge in the region. there must be excess positive or negative charge in the region. there must be a magnetic dipole in or near the region. there must be a magnetic dipole in or near the region. the electric field must be in the same direction as the magnetic field.