The second one is the best and most accurate translation, i.e. "Why should I speak to you at all?"
The whole verse 8:25 is "So they told him, "Who are you?" Jesus answered, "Why should I speak to you at all?"
and sometimes the translations omit the final question mark symbol of the original text of your phrase, which is " ελεγον ουν αυτω, Συ τίς ει; ειπεν αυτοις ο Ιησους, Την αρχην ο τι και λαλω υμιν;"
My original version of the New Testament, published by the Archdiocese of Athens, gives a question-mark for the end of the phrase.
However, if finally there is no question mark, the first translation you found applies best. I will try to check it out from other sources, too.
I hope it's clear now.