The correct answer is all of the above
Mixtecas: In English Mixtec, are indigenous Mesoamerican peoples of Mexico. They inhabit the region known as La Mixteca of Oaxaca and Puebla as well as the state of Guerrero's Región Montañas, and Región Costa Chica, which covers parts of the Mexican states of Oaxaca, Guerrero and Puebla. They are divided into three groups, two based on their original economic caste and one based on the region they settled. High Mixtecs or mixteco alto were of the upper class and generally richer. On the other hand, the Low Mixtecs or mixteco bajo were generally poorer.
Zapotecas: In English the Zapotec civilization was an indigenous pre-Columbian civilization that flourished in the Valley of Oaxaca in Mesoamerica. According to the archaeological evidence their culture goes back at least 2,500 years.
Olmecas: In English, the Olmecs were the earliest known major civilization in Mexico developing its culture in Soconusco. They lived in the tropical lowlands of south-central Mexico. Nowadays states of Veracruz and Tabasco