This is my effort. I think it is a bit easier to read, as "declared preferring having the possibility to choose among", for me, is hard to follow and would need read a couple of times maybe to be understood. Maybe it's just me
"22% of the interviewed guests said they would prefer to have the possibility of choosing from a selection of European dishes"
I am not sure but also declare seems a bit over the top-as I dont know if a guest would declare to want something?