I'd choose to serve the elder, as I think there might be less chance I'll die, because they relate to anyone as insects. Therefore, unless I stand out too much, they probably won't kill me.
Def not Akainu because he would get mad and turn me into a donut. Not Big Mom bc I'll be SO afraid of her and then I will get my soul stolen. Caesar clown I would be experimented on. Magellan Is literally death by touch. So it's between crocodile or one of the Gorosei