The Discovery of the Gravitational Lens Effect for Quasars

The discovery of the gravitational lens effect for quasars

A) shows that quasars were located within the local group of galaxies.
B) shows that quasars were giant planets in our solar system.
C) shows that quasars are much further away than the distant galaxy that forms the gravitational lens.
D) proves Newton's theory of gravitation by showing that the photon is affected by gravity.
E) proves the existence of supermassive black holes at the center of active galactic nuclei.