Daffy Duck's a pretty laid back guy. He won't mind if you use either one.

I would use A).

 

 

I use method B.

The logic is that the address should read less specific to more specific from the bottom up.

zip code
state
city
street address
occupant name (be it a person or a company)
and finally internal delivery instructions (attn: person xyz).

 

A

 

I vote on A too.