A line that's 'normal' to the surface is perpendicular to the surface.
The angle of incidence is the angle between the normal and the light ray ARRIVING at the surface.
The angle of reflection is the angle between the normal and the light ray LEAVING the surface after it's reflected.
The law of reflection says these two angles are equal.
I'm 99% sure that it's "D. Electric Field"
A series circuit has only one path for current,
while a parallel circuit has more than one.