Head like an orange
You choose which solution of an encounter you resolve.
You can choose that but not build the structure (it might give you something else) but the better thing would probably be to choose another resolution.
If an Encounter card gives me the option to build a structure the rules say that I have to build it in the hex where the encounter happened.
What if a structure has already been built in that hex?
Do I have to choose another option from the encounter card or can I build the structure on any other hex with one of my workers on it?