Answer: The right answer is the C) ¡Venga a nuestra casa!
Explanation: Just to elaborate a little on the answer, it can also be added that when addressing an elderly aunt you most likely would use the personal pronoun "usted." Therefore, the right form of the imperative form of the verb "venir" (to come) in that personal form is "venga." "Venimos" would be used with the first person plural (nosotros), and you only use the imperative with the second person singular and plural. The same goes for "viene," which refers to the third person singular (ella). "Ven" is used with the personal pronoun "tú," which would be used when using the imperative with a younger relative or with someone you know closely and can address less formally.
Cuando llegó la ambulancia, el esposo estaba mareado.
The verb llegó is in "Pretérito Indefinido" or "Pretérito perfecto simple" this tense talks about an action that happened at a specific time in the past and finished
El verbo estaba is in "Pretérito Imperfecto" this tense ephasizes in the progress of an action.