The Meaning of the Phrase "Space Is Relative" Is That

Multiple Choice

The meaning of the phrase "space is relative" is that

A) all observers measure the same speed for a lightbeam.
B) two observers, in different reference frames, observe different lengths for the same object.
C) two observers, both in the same reference frame, observe different lengths for different objects.
D) two observers, in different reference frames, observe different lengths for different objects.
E) two observers, both in the same reference frame, observe different lengths for the same object.