A Black Hole Is So Named Because

A black hole is so named because:

A) the gravitational field is so high that the wavelength of its emitted light is gravitationally redshifted to radio wavelengths.
B) it emits no visible light because it is so cold, less than 100 K.
C) no light can escape from it due to its powerful gravitational field.
D) it is colder that the rest of the universe; that is, its effective temperature is less than 3 K.