Why are the variable head groups in sphingomyelin, such as phosphocholine and phosphoethanolamine, significant?

• A. They are responsible for the hydrophobic properties of sphingomyelin.
• B. They determine the fatty acid chain length in sphingomyelin.
• C. They are involved in the synthesis of glycerophospholipids.
• D. They contribute to the amphipathic nature of sphingomyelin, making it suitable for membrane structure.

Answer: (D)