The correct answer is A) prevent infection. Antiseptics are substances used to kill or prevent the growth of microorganisms, such as bacteria, viruses, and fungi, on the skin or other surfaces. Their primary purpose is to reduce the risk of infection by eliminating harmful microbes that could otherwise enter the body through wounds, cuts, or other openings. This helps prevent infections and supports the body's natural healing process. The other options are not the primary functions of antiseptics. Increasing blood circulation, reducing inflammation, and speeding healing are secondary effects that may occur as a result of preventing infection, but they are not the main purpose of using antiseptics.