According to the special theory of relativity, all laws of nature are the same in reference frames a. that move at constant speeds. b. that accelerate. c. that vibrate. d. that oscillate. e. none of the above

According to the special theory of relativity, all laws of nature
are the same in reference frames that move at constant speeds. 

That means that there's no test or measurement you can do to
detect whether you're moving at a constant speed or how fast. 
And THAT means that there's no such thing as "who's REALLY
moving" and "who's REALLY at rest".  There's no such thing as
"real" motion, only motion relative to something else.

The masses of the objects and their densities