Observer S and Observer T each measure the velocity of the same car that is traveling east along a straight road. Observer S reports the car’s velocity as “20 m/s east,” while Observer T reports it as “12 m/s east.” Which of the following statements must be true about the motion of Observer T relative to Observer S?
a) Observer T is stationary relative to Observer S.
b) Observer S is moving west relative to the ground while Observer T is stationary.
c) Observer T is moving east relative to Observer S.
d) Observer T is moving west relative to Observer S.