Question

Which statement about black holes is true? A. light can escape but matter cannot B.
Nothing, not even light, can escape C. They are visible with optical directly D. They do not exist,
only theoretical model

Answer 1

B.

In general relativity a black hole has an event horizon — a boundary inside which nothing, not even light, can escape to the outside. (Quantum effects such as Hawking radiation cause very slow emission from a black hole as a whole, but that is not the same as ordinary light escaping from inside the horizon.) Observational evidence for black holes includes stellar orbits around Sgr A*, X‑ray emission from accretion, gravitational waves from mergers, and the Event Horizon Telescope image of a black hole’s shadow.