What Is the Meaning of the Schwarzschild Radius Around a Black

Multiple Choice

What is the meaning of the Schwarzschild radius around a black hole?

A) It is the radius at which an orbiting object would show a precession.
B) It is the radius at which gravitational redshift can be detected.
C) It is the radius at which the black hole's spin equals the speed of light.
D) It is the radius at which the escape velocity equals the speed of light.
E) It is the radius at which a body falling onto the black hole would move at half the speed of light.