Sort the choices by how they affect heart health. Palmitic and stearic acids are long-chain saturated fats, the type linked with rising LDL cholesterol and atherosclerosis, so they cannot be the protective option. Oleic acid is monounsaturated and reasonably heart-friendly, yet it is not the standard textbook answer for a cardioprotective fatty acid. The omega-3 polyunsaturated fatty acids, including EPA, DHA, and alpha-linolenic acid, are the recognised cardioprotective fats: they cut triglyceride levels, stabilise heart rhythm, reduce clot formation, and lower coronary disease risk. Therefore, among the given options, omega-3 fatty acids are cardioprotective.
\[\boxed{\text{Omega-3 fatty acids}}\]