One of the weaknesses of government codes of ethics is that these codes _____.
a. Typically require of government officials much higher standards than are required of citizens at large
b. List standards that are virtually impossible to attain consistently since these codes are written at the theoretical level
c. Involve provisions that vary widely and change every year, leading to problems in implementation
d. Tend to be so wide in scope that they severely curtail the operational freedom of government officials