For what purpose might a prophylactic be given?

A prophylactic is specifically designed to prevent illness or disease before it occurs. This can include measures such as vaccinations, medications, or interventions that aim to reduce the likelihood of infection or disease manifestation. By administering a prophylactic, healthcare providers can help individuals avoid health issues that might arise due to various risk factors.

In the context of the other options, while enhancing recovery after surgery, relieving symptoms of a chronic condition, or enhancing athletic performance might be important aspects of healthcare and treatment, they do not align with the primary purpose of prophylactics. They are not primarily focused on prevention, which is the key function of a prophylactic. Thus, the emphasis on preventing an illness distinctly identifies the correct answer.