A Reason Why Agricultural Cartels Are Not as Effective as OPEC

Multiple Choice

A reason why agricultural cartels are not as effective as OPEC is that non-member countries can:

A) increase their supply of crops but not their oil supply.
B) decrease their supply of crops but not their oil supply.
C) increase their oil supply but not their supply of crops.
D) decrease their oil supply but not their supply of crops.