Will give brainiest answer if you answer both questions.

1 is incorrect because yo is I and the bailaban is talking about other people not you or I, so it should have been yo baílaba, or yo baíle.
2 is incorrect because it’s saying they playing which doesn’t make sense , in other words, it should have been ellos jugaban because you use jugabas for talking to someone else, you can for example ask someone: “tú jugabas?” But can’t say ellos jugabas.
Hope this helped :)

B. comprarías is the correct answer

An infinitive ! hope this ! mark as brainlest and say ! xx