For this case we can translate the sentence as:
<em>The orchestra has a concert tomorrow. That's why_____.</em>
We must complete the space with one of the following options:
<em>They sing, they rehearse, they record, they play</em>
The option that most fits is the B. Before a concert is necessary to rehearse.
Answer:
La orquesta tiene un concierto mañana.Por eso ensayan
