The correct answer is C) Surgeons began replacing worn-out heart valves with artificial ones.
The medical advancement that occurred during the 1950s is "Surgeons began replacing worn-out heart valves with artificial ones."
During the 1950s, medical researchers discovered new methods to help people with heart diseases. Some great examples are the pacemaker, better techniques for open-heart surgery, and the invention of the artificial heart. These technological advancements represented the opportunity for patients to live a longer life or a quality life.