Hazel is the one to go for. We've already seen the casual voters won't go for the twins - being saved with least votes whenever they've been up. Hazel is the one to evict to keep Dexter in - it's between those two.
All nommed housemates' fans need to vote to evict Hazel to save your fave, except Hazel fans of course. They can vote for whoever, spread their votes over the others if they want.