The answer is A or Extrinsic
Reads like a martin luther king or like minded speaker going for freedom of speech and struggle for justice (against the apartheid that Rosa Parks also stood - or in her case literally sat - for). "Mississippi Burning" is a very powerful film.
The electromagnetic wave is self propagating, what I mean by that is, an electric field generates a magnetic field at 90 degree phase angle, and the magnetic wave you get as a result generates the electric wave at the same phase angle. The interchange of electric to magnetic and vice versa continues and lets the electromagnetic waves to travel without any medium. Quite interesting, really!
