单选题 According to this passage, ______may result in the imbalance of bacteria in your intestines.

A、 antibiotic treatment for an ear infection
B、 taking pills which contain freeze-dried germs
C、 eating yogurt or buttermilk
D、 eating products made from fermented milk

【正确答案】 A

【答案解析】[试题分析] 细节题。
[详细解答] 根据第二段最后一句话Bat if the bad outnumber the good—for example，after antibiotic treatment for a sinus or an ear infection，which kills normal intestinal germs as well—the result can be diarrhea，我们可判断，A为正确答案。