Which of the following statements are true concerning light? Choose all that apply

Which of the following statements are true concerning light? Choose all that apply.

a) The speed of light in matter is less than the speed of light in a vacuum.
b) Its propagation direction is parallel to both the electric field and the magnetic field.
c) The speed of light in matter is greater than the speed of light in a vacuum.
d) Its propagation direction is perpendicular to both the electric field and the magnetic field.
e) It moves at a constant speed through the vacuum.
f) The speed of light is the same no matter what material it is traveling through.