Option A: Llyria (my fictional planet) was originally called another name and that name was planet Earth. The human race that once existed on Earth died out for unknown reasons, and the race that currently exist on that planet are humanoid beings that are the descendants of an eldritch god who MIGHT be the real cause of why humanity no longer exist.
Option B: Humans never got to terraform the planet Mars to expand their growing population. Mars has become a new home to an alien race that is skilled at wielding super magical powers and are highly advanced at creating technology that surpasses what humans can only dream of doing.
Option C: Earth isn’t home to humanity because humans don’t even exist and never have. Earth is home to an entirely different race of beings that may look human but have a totally different biology. The home planet that humans actually live on is located in some other solar system.
Option D: Humans become slaves to an alien race of super tall humanoid beings that exist on both Mars and Venus. Planet Earth isn’t home to humanity or any other species. It is just a blue and green rock with population of zero. When humans traveled from their dying planet to reach Earth, they stumbled upon Mars and Venus only to get enslaved by the alien races that exist there. They never even gotten the chance to reach Earth…yet.
These are all science-fiction related. Which is really interesting to you, personally?