All of them. The general rule of thumb when seeking to serve someone: Blanket every possible address you have for them, but do it delivery restricted to an officer of the corporation you know will be at the address (i.e. Eduardo). That way you can prove that he, or an authorized agent, actually got the letter. All certified mail does is provide you with proof that it was delivered somewhere, if you aren't absolutely sure that's the right address you add restricted delivery so you can prove that not only did it arrive, but it arrived in the hands of the right person.