Mi ne povas decidi kio(n) paroli pri. (not sure about the accusative)
Mi ne povas decidi kion priparoli.
I've said something similar to #1 before not knowing whether it was okay or not. Someone pointed out to me that it probably would be better to say #2, but he wasn't completely sure either, as we are both newer Esperantists.
So, are either of these even correct? Is it wrong to end a sentence with the word pri? Is there a better way to say something like this?