A small contribution is the actions to get the value from the dropdown list.

I hop Nick can give the second part, compare the value to the score.

In a new document, 1 page, I put a dropdown element and gave it identifier q.
I made several items in the list:
Description - Value - Selected
make a choice - 0 - yes
choice 1 - 1 - no
choice 2 - 2 - no
choice 3 - 3 - no
The descriptions are important for your student; the values for the actions.

Then I put a button (object - form) on the stage, made it invisible and gave it identifier submit.

Then I put four textboxes on the stage, each one with the feedback. I gave them identifier u0, u1, u2, u3.
Contents:
u0: please make a choice and press 'submit'.
u1: you choose for '1'
u2: you choose for '2'
u2: you choose for '3'
I made all these four textboxes invisible.

On the dropdownlist I made action:
On Select Item
DISPLAY(Object='submit',Display='Show',Effect='Object',Duration='0')

On the submit button I made an action
IF(Condition='$q.value==0')
DISPLAY(Object='u0',Display='Show',Effect='Object',Duration='0')

and three more actions: if .. == 1 then display u1; 2 => 2 and 3 => 3.
Don't forgte the leading space in the line below the 'IF' statement, see another thread or Nick's site.

That's it.

Instead of using '$q.value' you might open the properties of the dropdown list and enter a Run-time variable name, I used ddVar.
Now the value is in a variable you can use in this page and if I remember well, in pages after this one.

The IF statements change in:
IF(Condition='#ddVar==0')
DISPLAY(Object='u0',Display='Show',Effect='Object',Duration='0')
etc.

Succes!