Nothing can be said with certainty about the stars based on the given options except (A) the blue star is hotter than the red star.
The color of a star is related to its temperature, with hotter stars appearing blue and cooler stars appearing red. Therefore, a blue star would be hotter than a red star.
The other options are not necessarily true for all red and blue stars. The distance of a star from Earth, its proper motion, and its radial velocity can vary greatly between different stars, regardless of their color. Similarly, the mass of a star is not necessarily related to its color.