Final answer:
None of the provided options are known to be the teacher of Nicolo Porpora. Apprenticeships were vital in artistic education during the Renaissance, as seen with artists like Sofonisba Anguissola and Properzia de Rossi.
Step-by-step explanation:
The student asked about the only teacher of Nicolo Porpora, an important figure in the history of music. None of the options provided, including Count Ferdinand von Morzin, Maria Anna Keller, the Esterhazy family, or Prince Anton/Nikolai, are known to have been Porpora's teacher.
In the context of the arts and music, it's well-documented that apprenticeships played a crucial role in the education of artists and musicians. Instances like Sofonisba Anguissola, having been able to study under Michelangelo due to her family's nobility, and Properzia de Rossi, who received formal training in marble at the university only after her talent was acknowledged, demonstrate the typical pathways to artistic education during the Renaissance era.
Unfortunately, there is no historical record indicating that any of the listed individuals were Porpora's teacher. Typically, a music historian or reference text on Nicolo Porpora would be the appropriate source to consult for the name of his teacher.