Name a common drug used to treat bacterial infections.

Antibiotics are a class of medications specifically designed to combat bacterial infections. These drugs work by targeting various processes essential to bacterial growth and reproduction, effectively killing the bacteria or inhibiting their ability to multiply. This makes antibiotics crucial in treating a wide range of infections caused by bacteria, such as strep throat, urinary tract infections, and bacterial pneumonia.

The other choices represent drug classes that address different types of pathogens or conditions. Antivirals are used to treat infections caused by viruses and would not be effective against bacterial infections. Antifungals target fungal infections and are irrelevant when it comes to bacteria. Corticosteroids are anti-inflammatory medications that can help reduce inflammation and suppress the immune response, but they do not directly treat infections; in fact, they may sometimes be counterproductive in the context of active infections as they can dampen the immune system's ability to fight off pathogens. Thus, antibiotics are the appropriate choice for treating bacterial infections.