Its A or C but i think A is the best answer. I hated this book lol.
Milton begins Paradise Lost by stating the theme of the epic, which is one of several epic conventions.
The first sentence of the poem is actually quite lengthy and tells the reader the poem will involve "Man's first disobedience, and the fruit Of that forbidden tree..." etc. etc.
Other conventions: the style is elevated and formal, and the setting is vast in scope.