Answer:
The sentence could take the place of: "Tú compras un boleto para ellos" is:
- Se lo compras.
Explanation:
The object pronouns are nouns that have their position in the complement of the sentence, in English these are me, you, him, her, it, us, and them, in Spanish are: me, te, se, and nos, their use is focused to the person who realizes the action for, in this case, it's focused to "ellos" whose object pronoun is "se" and the article that must be used is "lo".
