In the Science Fiction Book Series "Red Mars,Green Mars,Blue Mars

In the science fiction book series "Red Mars,Green Mars,Blue Mars" the author spins a story of "terraforming" Mars with the formation of oceans and a breathable atmosphere by the end of the series.The author describes a scenario,however,where the inhabitants of this fictional world were able to live relatively normally on most of the world but not on Olympus Mons and the Tharsus region.Assuming you could create a breathable atmosphere as described in the books,is the description of where you might live on Mars realistic,or just spinning a yarn?

A) No,it is absurd.Even with an atmosphere,it would be too cold to live anywhere on Mars.
B) Yes,because Olympus Mons and the Tharsus region are higher above the Martian plains than Mt.Everest,so the air would always be dramatically thinner and colder there,even with an Earth atmosphere.
C) No,because you could use water ice from these high altitude sites whereas there is no water at lower elevations on Mars.
D) No,because these regions are so rugged it would be impossible to live in the Martian mountains,regardless of an atmosphere or not.