Special relativity explains that the time seen from an observer in an inertial frame will pass slower than a clock that is at rest in its own frame of reference. This phenomenon is known as the dilation of relativistic time. That is to say that at a higher relative speed, there will also be greater dilation between them. Recall that the speed of light is approximately 300,000,000 m / s and therefore this rate of time will tend to be zero as it approaches this speed. For this reason the observer will observe that time passes slower in the nothingness of the partner than his.
The correct option is A.