Not previously attempted or embarked upon; untried:he had long dreamed of making the hitherto unattempted journey by car...
Milton himself, in the Argumentum that begins the poem, claims to have produced the greatest poem ever written, ‘things unattempted yet in prose or rhyme.’
In the case of an incorrect or unattempted question the actual answer will appear along side in red text.
You can also think of a case of leaving the question unattempted.