Where Do We Find Supermassive Black Holes

Where do we find supermassive black holes?

A) Only in the centers of giant elliptical galaxies
B) Only in the centers of active galaxies
C) In the centers of both active and normal galaxies,but only those at relatively high z values,indicating that they existed in the distant past
D) In the centers of both active and normal galaxies,both nearby and far away