<span>Tú compras un boleto para ellos.
From the options, it appears you need to write this sentence using a direct object pronoun. The object of the sentence is un boleto, which is masculine singular. This means the direct object pronoun must be masculine singular; the direct object pronoun must be lo.
This narrows the options to 1 and 2, however the first option can be eliminated due to grammatical error (los lo, which translates to "the the", doesn't make sense).
Answer:
</span>2) Se lo compras.
Mis últimas vacaciones fueron maravillosas. La pasé junto con dos amigos en Cantabria. Los paseos eran por las montañas eran una pasada y los campamentos que hicimos son cosas que a nadie se le olvida.
I'll let you do the rest. I started the paragraph talking about a trip you made to the north of Spain, Cantabria.
Hope it helped,
Happy homework/ study/ exam!