Final answer:
The correct answer is 'B. llegó'.
Step-by-step explanation:
The correct answer is B. llegó. This is the conjugated form of the verb 'llegar' in the third person singular, which matches the subject 'yo' (I). In Spanish, the verb form depends on the subject pronoun used. In this case, since 'yo' is the subject, we use the 'llegó' form.
Learn more about Verb conjugation in Spanish