Which of these best represents a fatty acid molecule?

 A fatty acid molecule is typically represented by a long hydrocarbon chain with a carboxyl group (-COOH) at one end. The hydrocarbon chain part is hydrophobic, meaning it does not mix well with water, while the carboxyl group is hydrophilic, meaning it can interact with water. Fatty acids can be categorized into saturated (no double bonds between the carbon atoms in the chain) and unsaturated (one or more double bonds in the chain).

A simple representation of a saturated fatty acid could be written as CH3(CH2)nCOOH, where "n" represents the number of the repeating CH2 units in the hydrocarbon chain.

An unsaturated fatty acid will have one or more double bonds, depicted as C=C, within the hydrocarbon chain. The location and number of these double bonds can affect the properties of the fatty acid. For example, an unsaturated fatty acid with one double bond could be represented as CH3(CH2)nCH=CH(CH2)mCOOH, where "n" and "m" indicate the number of CH2 units before and after the double bond, respect