Since flu viruses have been shown to be one of the major causes of bronchitis, ___________.

• A. acute and chronic bronchitis were both thought to be inflammations of the air passages
• B. infants, young children, and the elderly are more likely to get the disease
• C. The American Lung Association estimates that about 14 million Americans suffer from the disease
• D. getting a flu vaccine may also help prevent acute bronchitis