I would use Django for the implementation, rather than PHP, this way I can quickly setup an administration portal for you to manage the questions and options displayed on the site, as well as see the historical results.
I can pre-recreate a list of unique credentials for you to pass out, or give you a script to create them as and when needed.
I'd use a pre-prepared bootstrap theme (with any requested CSS changes) for an interface which dynamically changes in size to fit the viewing screen.
If you need the full E2E solution delivered then the stack i'd use would be a Ubuntu VPS, Nginx, Gunicorn, MariaDB.
Low bid has been given as i'm trying to build up feedback on my Freelancer profile.