Final answer:
The correct phrase that completes the sentence is 'l'ai acheté.' In this sentence, the pronoun 'l'' (meaning it) is used to refer to the online travel guide, and it agrees in gender and number with the direct object being referred to.
Step-by-step explanation:
The correct phrase that completes the sentence is OC. l'ai acheté.
In this sentence, the subject 'J'ai' (I have) indicates that the speaker (je) saw the online travel guide (le guide de voyage en ligne) and performed the action of purchasing it. In French, when the direct object is a pronoun, it must agree in gender and number with the direct object being referred to. Here, the pronoun 'l'' (meaning it) replaces the noun 'le guide de voyage,' and it agrees in both gender (masculine) and number (singular).
Therefore, the correct phrase is 'l'ai acheté' which means 'I have bought it.'
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