Are these sentences correct:
1-You have to make one single choice about all the cities that you are going to visit and decide whether you want three star or four star hotels.
2-You have to make one single choice covering all the cities that you are going to visit and decide whether you want three star or four star hotels.
(You don't make a choice at each city.)
They are both correct. The adjective "one single..." is a tautology though. I think it would be better to say either "a single..." or omit "single".