Final answer:
The adjective 'originaux' is the correct choice to complete the sentence.
Step-by-step explanation:
The correct adjective to complete the sentence is originaux.
'Nous voulions voir les documents historiques' translates to 'We wanted to see the historical documents.' In French, adjectives must agree in gender and number with the noun they modify. Since 'documents' is masculine plural, the correct form of the adjective is 'originaux'.
Learn more about French adjectives