The fact that quasars can be detected from distances where even the biggest and most luminous galaxies cannot be seen means that Select one: A. they must be in directions where intergalactic absorption by dark matter is minimum, allowing us to see them. B. they must be intrinsically far more luminous than the brightest galaxies. C. they have not been as redshifted by their motion as have galaxies, and hence they can still be seen. D. they must be in directions where gravitational focusing by the masses of nearer galaxies makes them visible from Earth.