The "Further" We Are Temporally from a Future Generation, the Weaker

The "further" we are temporally from a future generation, the weaker our obligations become toward them, because

A) we are more alike and equal to those nearer to us.
B) our knowledge and ability to control events becomes less over longer periods of time.
C) temporal distance from people always weakens every obligation to them.
D) we can only be held responsible for how our actions affect the people alive today.