Is fermentation a type of aerobic or anaerobic activity?

Flexi Says:
Fermentation is a type of anaerobic respiration that includes glycolysis followed by the conversion of pyruvic acid to one or more other compounds and the formation of NAD+.
Fermentation is a type of anaerobic respiration that includes glycolysis followed by the conversion of pyruvic acid to one or more other compounds and the formation of NAD+.