Which of the following best defines sphingolipids?

• A. Lipids containing a sphingosine backbone and classified by their variable head groups.
• B. Lipids containing a ceramide backbone and classified by their sugar residues.
• C. Lipids containing a phosphate group and classified by their saturation level.
• D. Lipids containing a glycerol backbone and classified by their fatty acid chains.

Answer: (A)