Bacteria cultures that have been allowed to undergo fermentation have been used commercially for centuries in the production of
a. bread
b. beer
c. wine
d. yogurt

The right answer is D. Yogurt

Bread, beer, and wine are also prepared by fermentation, but the micro-organisms here are the yeast, not bacteria.

Yogurt is a milk fermented by the development of lactic acid bacteria Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus which must be sown simultaneously and be alive in the finished product.

it would lead to upper respiratory infections and pneumonia.