单选题 What is the main idea of this passage?

A、 We don't need to worry too much about bacteria everywhere in our life.
B、 Antibacterial products for the home are found to be effective.
C、 The TV advertisement the writer mentioned is a total failure.
D, The existent bacteria pose a threat only to the very young and very ol

【正确答案】 A

【答案解析】[解析] 综观全文，本文的主旨应是我们不必过度担心生活中无处不在的细菌。因此A项为正确答案。