When do they plan to get married?
When do they plan to get married? (going).
When do they plan to get married? (going).
En resumen
When are they going to get married.
When are they going to get married.
When are they going to get married?
We will phone you when we get there.
What time do they get up?
Respuesta : C. Are going to be marriedExplicación : es la C ya que la oración esta en futuro y para el futuro es usa el going to y como se usa el pronombre we la conjugación del verbo to be para dicho pronombre es are.