According to introduction to dark romanticism american gothic how does poe's writing distinguish his works from other romantic authors ?

It distinguishes it because he takes a far darker approach to his writing. In those days, a lot of people made romance with a central conflict, but then made everything turn out relatively good in the end. In Poe's stories, he uses fear and tragedy do make his stories a lot more scary and original.  

The third answer is correct.

Rhyme is can both understand what the writer is writing about clearly you know the consign words will rhyme