Final answer:
The correct preterite form of the verb 'asistir' is 'asistí'.
Step-by-step explanation:
The correct answer is OD. asistí. The verb asistir means 'to attend' and is conjugated in the preterite form as asistí for the first person singular pronoun 'yo' (I). In this sentence, the subject 'yo' (I) is attending the school, so the correct preterite form is asistí.
Learn more about Spanish verb conjugation