it is an MCQ of microeconomics, please explain all the options why it is true and why it is false

O c. Collusion profits are smaller than Cournot equilibrium profits O d. Collusion is hard to achieve between sellers choosing price but easier when they choose quantities Which of the following method(s) of pricing enable a public utility to reduce the variance in its revenue as demand or load fluctuates? Select one: O a. Fixed charge b. Decoupling O c. Two-part pricing O d. All options are applicable Equilibrium profit for each (identical) seller in a Bertrand Duopoly is