Yo no _____________________ de México.

The subject is “yo” (“I”), and “ser” is used to describe where someone is from. The correct form of “ser” with “yo” is “soy,” so the sentence is “Yo no soy de México” (“I am not from Mexico”). “Estoy” means “I am” for a temporary state or location, not origin.

AI-written and checked against the verified answer.