@centrox,
Quote:c. not one
This phrase means 'none of a group or collection' e.g. not one of the boys could swim; not one of the houses had a garage.
And 'none' can replace 'not one' in each of your example sentences, can it not, centrox?
And in the original question,
He was surprised to see a shop where _________ had existed before.
a. none
b. no one
c. not one
d. never
both a. and c. are possibilities.