Which fatty acid is 18 carbon monounsaturated with one double bond and commonly found in olive oil?

• A. 16 carbon polyunsaturated fatty acid with multiple double bonds
• B. 20 carbon saturated fatty acid with no double bonds
• C. 18 carbon monounsaturated fatty acid with one double bond
• D. 22 carbon fatty acid with two double bonds

Answer: (C)

Olive oil is particularly rich in oleic acid, which is an 18-carbon monounsaturated fatty acid with a single double bond (18:1). The defining features here are the chain length (18 carbons) and the degree of unsaturation (one double bond). That exact combination describes oleic acid, the fatty acid most associated with olive oil. The other options describe fatty acids with different chain lengths or degrees of unsaturation (for example, saturated with no double bonds, or polyunsaturated with multiple double bonds), so they don’t match the characteristic profile of olive oil.