Why Is It Not Possible to Use Visible Light to Investigate

Why is it not possible to use visible light to investigate the center of our Galaxy?

A) Intervening gas locating in the disk of the Galaxy blocks our view of the Galactic center.
B) The massive black hole located at the center of the Galaxy prevents light from escaping the region.
C) There are no sources of visible light found at the center of the Galaxy.
D) The density of stars toward the Galactic center is so high that it is not possible to see through them.