Martians or Aliens, oppose to Zombies and other monsters, cause a unique fear because of the fact that outer space scares us. I mean, why shouldn't it? Space is a cold desolate place bigger than we could possibly imagine, whereas the earth, where we live, is mostly explored. That's not even including all the rumors about Alien cover-ups by the government.
Most likely personal memoir. It states the things that happened to you in your life and reflects on those events. It could contain some persuasive content but nothing compared to the other options.