c. If you don't want Halsin's help or don't want to help him - fine. You know what you can do? Kill Minthara and talk to her corpse. She'll tell you where to go next. She'll point you to moonrise tower or whatever the name.
Hmm. The game actually explicitly tells you that corpses won't talk to their killers. It's even in the hints on the loading screens. So I never bothered.
