Which of the Following Explains the Difference Betweencommand and Control

Which of the following explains the difference betweencommand and control policies and tradeable allowances?

A) Command-and-control policies are a government solution to externalities, whereas tradeable allowances are a type of
Private market solution.
B) Tradeable allowances allow for less flexibility than command and control policies.
C) Command-and-control policies require all firms to reduce pollutants by a specific quantity, whereas tradeable allowances
Allow some firms to pollute more than others by trading for
Pollution rights.
D) Tradeable allowances sometimes result in higher overall levels of pollutants because firms can simply purchase the
Rights to pollute more, whereas the quantity of pollution is
Fixed under command and control.