The Existence of Supermassive Black Holes in the Centers of Many

Multiple Choice

The existence of supermassive black holes in the centers of many galaxies has been inferred by what definitive measurement?

A) The measurement of extremely dark regions of space in the centers of galaxies,from which no radiation is seen
B) Measurement of very rapid orbital motion of objects around a very massive central object
C) Bending of light from stars on the far sides of galaxies by a very massive central object,as seen from Earth
D) Detection of very specific electromagnetic emissions predicted by theory to be emitted by a massive black hole