Final answer:
The appropriate preterite form of the verb 'asistir' to fill in the blank with 'Yo' is 'asisti'.
Step-by-step explanation:
The appropriate preterite form of the verb 'asistir' to fill in the blank with 'Yo' is option C. 'asisti'. In Spanish grammar, the preterite tense is used to talk about completed actions in the past. In this case, 'asistir' means 'to attend', so 'asistí' is the correct form to complete the sentence 'Yo asistí a la escuela.'
Learn more about Spanish verb conjugation