3, but u want to be prepared for specific poems, e.g. must discuss 'x' as part of. so have extra paragraphs/quotes etc. for other poems.
the common formats are.
let poems be a,b,c.
you can have intro a b c conclusion
or intro a&b b&c c&a conclusion, discussing a common idea between two in each para.
You could also have other structures, e.g. free flow discussion. bring in any poem in any para whenver u want or a&b c&d e&a&b etc.
if u do the first structure, maybe have some links between poems during paragraphs, because the poems are part of a collective work and u should make markers realise that you know this. look at hsc marking feedback.
the second structure makes a better/more elegant essay when done well imo. However, it is much harder to execute properly. I did this (notes & resources) and found myself spending a lot more time figuring out my eliot essay structure than any other modules.