Final answer:
The correct answer is 'l'ai lu'.
Step-by-step explanation:
The correct answer to complete the second sentence is l'ai lu. In French, the pronoun 'je' (I) is followed by the auxiliary verb 'ai' (to have) for past tense constructions. The verb 'lire' (to read) is conjugated as 'lu' in the past participle form. Therefore, the correct option is 'l'ai lu' which translates to 'I have read it.'
Learn more about Completing sentences in French