Which ISO Wiring Adaptor

Hi People im looking at fitting an Kenwood single Din Headunit to my Mrs 1999 2.8 V6 Audi A6 Which Has The Bose Sound System
The Problem I Am Having is Notifying Which Harness Do I Need To Do So As i Still Want to Keep The Bose Speaker System

I notice there is 3 Different Types Which One Will I need ????


PC9 - 401
PC9 - 404
PC9 - 408


Kind Regards Kelvin

Magic Thanks For pointing me in the right direction