Final answer:
Mixtures of fats and oils that are converted to fatty acids by heat and then purified fall under the classification of fatty acids.
Step-by-step explanation:
Fats and oils can be converted into fatty acids by a process called hydrolysis. When triglycerides (which are esters composed of three fatty acid units linked to glycerol) undergo hydrolysis in the presence of a base, they are converted into fatty acids and glycerol. This process is used to make soap and is called saponification. So, the correct classification for mixtures of fats and oils that are converted to fatty acids by heat and then purified is B. Fatty acids.