Mi hermana una invitación a una fiesta grande. a. recibir b. recibimos c. recibió

The word recibió tells us the tense of the sentence. So this sentence stands for the preterite tense because recibió is the conjugation of the verb recibir that matches the third person singular in the preterite tense. The preterite tense is one of two simple past tenses. It is used to describe actions that took place or were completed at a certain point in the past. So my sister got an invitation to a big party. Finally:

Mi hermana recibió una invitación a una fiesta grande