The Event Horizon of a Black Hole Is Defined as

Multiple Choice

The event horizon of a black hole is defined as

A) the point of maximum gravity.
B) the radius of the original neutron star before it became a black hole.
C) the radius from which shock waves course through spacetime due to the strong gravitational distortion of the black hole.
D) the radius at which the escape speed from the black hole equals the speed of light.
E) the radius at which the gravitational force is the same as that on the surface of the Sun.