Cortan because ellos means they and they is plural. Corta would be for ella/el/usted
The answer would be me lavo because me lavo means washing
According to the option provided the answer would be "¡ Ella está guapa en su traje de novia!" This would mean that she is pretty in her wedding dress.
if we pay attention to the verb form, it might be said that it agrees in gender and number with the subject pronoun "ella". It is 3rd person singular and feminine. <span />
The answer would be estudian