What is the role of reazurin in fluid thioglycollate medium, TGYA shake tubes, and Brewer's anaerobic agar? Multiple Choice a Reazurin indicates the presence of oxygen in the media. b Reazurin indicates the temperature of the media. c Reazurin indicates acid production by fermenting bacteria. d Reazurin indicates the presence of contaminating bacteria in the media. e Reazurin indicates the presence of CO2 in the media.