A、Antibiotics. B、Syrup. C、Zinc pills. D、Vitamin D. C由原文可知，摄入维生素C对一般人来说只能降低3％患感冒的风险，而服用含锌的药丸被证明是更有效的方法，有一些证据表明它可以缩短一天左右的感冒时间。因此答案

The apparent benefits of many of the treatments of a cold—such as dosing up on vitamins or snorting saltwater—evaporate under scrutiny. So what works and what doesn’t?
    Dosing up on vitamin C has been shown to mildly protect people under great physical strain from falling ill, but for the average person it reduces your risk by just 3％. Zinc pills may have a firmer footing. There is also some evidence that it can reduce the duration of a cold by a day or so. Given that zinc tastes unpleasant, and you would need to take it all year round for the full benefit, we are not sure if we would recommend it for general use.
    It’s commonly held wisdom that drinking too much alcohol at night will weaken your body’s defense and make you open to attack from viruses. The question has not been widely explored by doctors, but three independent studies suggest that regular drinkers are in fact less likely to catch a cold. Your choice of alcohol seems to matter—wine helps whereas beer does not. Even so, this is only preliminary evidence and should be taken with reasonable skepticism, but it at least suggests that you need not blame self-indulgence for your suffering.
    Don’t take antibiotics. but do consider cold relief pills. Put bluntly, there is no reason why antibiotics should help—since they target bacteria, whereas it is a virus that causes a cold. There’s no real benefit from antibiotics, but they do increase the risk of adverse events. Your best bet is to try to reduce your symptoms. Painkillers help relieve some of the symptoms for adults (not children). But even then, the benefits probably differ between people.
    In general, herbal remedies fail to deliver the goods. The only one to show any promise is honey. A spoonful, taken straight before going to bed, was found to soothe a cough in three different studies, and proved better than other sugary drinks and cough syrups. Even so, the remedy has mostly been tested on children. And the mechanism is far from clear.
    There are plenty of other questions that could be explored with further research. But by far the best measure is to simply use your common sense—wash your hands regularly and don’t share drinks with people who are already infected.
    Questions 19 to 22 are based on the recording you have just heard.
    19. What does the speaker say about the effect of snorting saltwater in curing a cold?
    20. Compared with vitamin C, which is more effective in reducing the duration of a cold?
    21. What can we learn about the relation between drinking and cold?
    22. Why shouldn’t we take antibiotics when catching a cold?