Hasta luego is an expression used to say good bye. From all the options provided is the only one correct. "Hola" and "Buenos" días are both opening phrases. They mean "Hello" and "good morning", so they wouldn't make sense in that part of the dialogue. "Más o menos" means "so so" or "not too good". This also doesn't make sense in that part of the dialogue.
Yo compré muchos libros. Tú escuchas musica latina. Nosotros aprendemos español con la maestra. Los amigos viven en Cantroamérica. Nosotros escribimos oraciones en español. Yo viajé a California hace un mes. Tú bebes mucha cocacola.
