The EM waves do not transport

The electromagentic waves do not transport

(A ): Speed of EM wave in a medium depends on electrical permittivity and magnetic permeability of the medium (R) E.M wave transport energy in the form of oscillating electric and magnetic fields

The figure here gives the electric field of an EM wave at a certain point and a certain. The wave is transporting energy in the negative z direction. What is the direction of the magnetic field of the wave at the point and instant?

What are EM waves?