Which of the following is the best definition of an unsaturated fatty acid?

Unsaturated fats are fats or fatty acids that are liquid a room temperature. Unsaturated fats are derived from plants and some animals. They contain at least one double bond in their fatty acid chain. Conversely, a saturated fat has no double bonds meaning it is saturated with hydrogen atoms.

An unsaturated fat is a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fatty acid chain is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond.

- Wikipedia