Black holes cannot be seen without X-rays. If a telescope focuses on X-rays, we see a bright spot surrounding the black hole and a larger doughnut-shaped mass around that. The bright spot is gas, glowing at one million degrees. Any visible light it makes is absorbed by the doughnut-shaped mass of dust and gas around it. So we can only see it using X-rays. This is called a hidden or buried black hole.
What does the photograph show to support the paragraph?
A. a black hole seen in visible light without X-rays
B. a buried black hole that looks like a doughnut
C. million-degree gas inside a black hole
D. visible light and dust outside a black