Which of the following statements most accurately describes Einstein's first postulate of special relativity?

W) The speed of light in a vacuum is the same in all inertial reference frames

X) The laws of physics are the same in all inertial reference frames

Y) It is impossible for an observer to travel at the speed of light in a vacuum

Z) An observer cannot discern between inertial acceleration and acceleration due to gravity
X) THE LAWS OF PHYSICS ARE THE SAME IN ALL INERTIAL REFERENCE FRAMES