What Is It That Keeps Localized Regions of Space, Such

Multiple Choice

What is it that keeps localized regions of space, such as things on Earth, planetary systems, star clusters, and whole galaxies, from participating in the general expansion of the universe?

A) their locations in places where irregularities in the chaotic Big Bang explosion permitted matter to condense
B) mutual gravitational attraction between objects in these systems
C) centrifugal force produced by the motion of the regions around a massive central object (e.g., the Sun, a supermassive black hole, etc.)
D) powerful and all-pervading gravitational pull from the central supermassive black holes of galaxies that holds everything in the galaxies in place