How Do Beauchamp and Childress's Four Principles of Biomedical Ethics

How do Beauchamp and Childress's four principles of biomedical ethics relate to what they describe as the common morality?

A) The principles are drawn from the common morality for the purpose of reasoning about biomedical ethics.
B) The principles provide a description of the main content of the common morality.
C) The common morality is derived by various groups and cultures from the principles.
D) Nonmaleficence and beneficence are derived straightforwardly from the common morality, but respect for autonomy and justice need further justification.