For those who were playing the home game (assuming the "pinot noir sauce" in question was a spin on marchand du vin), the answer was: demi-glace and/or espagnole, depending on whether the instructor considers demi-glace as a "mother."
The great classifiers of the late 19th and early 20th C. did not. But since their time it has not only become increasingly popular to do so but to make demi-glace directly from stock without resorting to its traditional espagnole mother.
To Mkay the OP:
Why you, I oughtta. If you actually pay attention, you'll get more out of the whole school experience. To repeat Pete... A jus is NOT a mother sauce.
Maybe it's not you. Where are you going to school? Josey Wales? Le Cordon Taché?