If you don't mind splitting1 the administration, you could use a Google Docs Form.
Get answers to your questions
Create simple or in-depth online surveys. Share them from a link,
embed them on your website, or even right inside an email.
Sit back and watch the results come in
All responses to your questions are neatly organized in a Google
spreadsheet, so sorting and analyzing data is a snap.
Then, it's a matter of using the embed code to display the Quiz in a page/post.
Haven't used none yet, but there are some few interesting plugins to integrate gDocs in WordPress.
1 - Without splitting
The following method is just a random idea and may have shortcomings that I'm not aware, but behaved quite well in my tests.
The code will create an administrative menu item that embeds the editing of an specific gDocument in WordPress dashboard. What's displayed in the dashboard are the results of the quiz in a Spreadsheet. The Form editing is done through the menu
Form (2) (opens a pop-up).
// Reference: http://codex.wordpress.org/Plugin_API/Action_Reference/admin_menu
if( !current_user_can( 'install_plugins' ) )
// Reference: http://codex.wordpress.org/Function_Reference/add_menu_page
// Check it, specially regarding the last parameter ($position), i.e.: 6
'<span style="color:#000;">Google Docs</span>',
6 // position, just after Posts
/* INSERT THE REAL DOCUMENT KEY */
width="100%" height="700" />
For the score issue, this tutorial has the Spreadsheet formula solution.