Q4

Which of the following statements is true regarding the observations of two people, one travelling at $99.9\%$ of the speed of light, and one stationary?
(A) Both people will observe time to be passing at the normal rate in their frame of reference.
(B) The person travelling at $99.9\%$ of the speed of light will observe their time to be passing slower.
(C) The stationary person will observe their time to be passing slower.
(D) Both people will observe time to be passing slower in their frame of reference.