In Einstein's Special Theory of Relativity, There Is One Basic

Multiple Choice

In Einstein's special theory of relativity, there is one basic principle [or assumption, or law] that seems very odd to our intuitions, and that is responsible for the odd nature of Einstein's conclusions. This basic principle is

A) the idea that mass is relative, and is larger when it is moved faster.
B) the idea that all motion is merely relative motion, i.e., that it is impossible to determine how fast you are moving without measuring against something outside your laboratory.
C) the idea that light has the same speed for all nonaccelerated observers.
D) E = mc².
E) relativistic length contraction.