Final answer:
The mother sauce demoted to a secondary sauce of velouté was Espagnole. This reflects changes in the classification of sauces in French cuisine, with Sauce Allemande, a derivative of Velouté, used as an example.
Step-by-step explanation:
The mother sauce that was demoted to a secondary sauce of velouté is a) Espagnole. In classical French cuisine, there are five mother sauces from which secondary sauces are derived. These mother sauces include Béchamel, Espagnole, Velouté, Tomato, and Hollandaise. A notable secondary sauce of Velouté is Sauce Allemande, which was formerly considered one of the main mother sauces before being reclassified as a derivative of Velouté.
As students of culinary arts learn, Espagnole itself is a robust sauce but isn't directly used over food. Instead, it serves as a base for other sauces, like Demi-glace, and therefore isn't considered a secondary sauce of Velouté. When studying mother sauces, it's important to comprehend the evolution of sauces and how the culinary arts canon has been adapted over time to simplify classifications.