The correct option is B Lactic acid
Lactic acid fermentation is a biological process by which glucose and other six-carbon sugars are converted into cellular energy and the metabolite lactate. Lactic acid fermentation is caused by some fungi and bacteria. The most important lactic acid producing bacteria is Lactobacillus. The presence of lactic acid, produced during the lactic acid fermentation is responsible for the sour taste and for the improved microbiological stability and safety of the food. This lactic acid fermentation is responsible for the sour taste of dairy products such as cheese, yoghurt