Final answer:
The correct verb form is 'salí' as it matches the subject 'yo.'
Step-by-step explanation:
The correct verb form to complete the sentence is c. salí. The subject 'yo' corresponds to the first-person singular of the verb 'salir' (to go out). Since the sentence refers to Sonia's New Year's Eve celebration, the correct form is 'salí' (I went out).
Learn more about Verb forms in Spanish