Which of the following is an example of a local infection?

A local infection is confined to a specific area of the body and is typically characterized by symptoms such as redness, swelling, pain, and pus. Pimples, also known as acne lesions, represent a localized infection that occurs in hair follicles and sebaceous glands, mainly on the skin. They result from the buildup of oil, dead skin cells, and bacteria, leading to inflammation and the formation of pus in that specific area.

In contrast, conditions like pneumonia and flu are systemic infections, affecting the entire body or specific organs, and are not limited to a single localized area. HIV is a viral infection that affects the immune system as a whole and does not represent a localized infection. Thus, the presence of pimples distinctly identifies them as local infections, making them the correct choice in this context.