What role does steric hindrance play in the Ramachandran plots of glycine and proline?

• A. Steric hindrance allows both glycine and proline to have similar plots.
• B. Steric hindrance has no effect on either glycine or proline.
• C. Steric hindrance affects glycine more than proline.
• D. Steric hindrance limits proline's bond angles but allows glycine more flexibility.

Answer: (D)