The Doctor's reality (An Unearthly Child)

In Auld Mortality's universe, the Doctor asked Susan to come with him as he made his escape from Gallifrey, and the Possibility Generator detected several branching timelines in which she agreed, (AUDIO: Auld Mortality) including one where the Doctor and Susan came to live in Barnes Common (PROSE: Doctor Who in an Exciting Adventure with the Daleks) and one where the Doctor and Susan came to live in Totter's Lane. (TV: An Unearthly Child)

However, other parallel possibilities involved Susan saying no, (AUDIO: Auld Mortality) and further accounts showed the Doctor living a parallel version of the First Doctor's life in which Susan declined and the Doctor subsequently never met Ian Chesterton and Barbara Wright. (AUDIO: A Storm of Angels, PROSE: The Innocents)

Behind the scenes

 * From what it described as "film evidence", the Dalek Survival Guide was aware of an alternative version of the Dalek Invasion Force (PROSE: Dalek Survival Guide) who were defeated by the version of Dr. Who who had a niece called Louise and a granddaughter called Barbara in addition to his granddaughter Susan. (NOTVALID: Dr. Who and the Daleks, Daleks' Invasion Earth 2150 A.D.) The guide identified this Dalek Invasion Force as hailing from a "version of history B" relative to the First Doctor's "version of history A". (PROSE: Dalek Survival Guide)