marks. The Australian government has authorised Pfizer and AstraZeneca to produce and sell COVID-19 vaccines. Each firm must decide whether to charge 'high price' or 'low price'. If both firms charge 'high price', then each would make a profit of $150 million. If both charge 'low price', then each would make a profit of $100 million. If Pfizer charges 'low price' while AstraZeneca charges 'high price, then Pfizer would earn $200 million and AstraZeneca would earn $60 million. If Pfizer charges 'high price' and AstraZeneca charges low price, then Pfizer would earn $60 million and AstraZeneca would earn $200 million. The information above suggests Pfizer and AstraZeneca are a duopoly operating in an oligopoly market. Use the information to answer the following questions. a. Derive the payoff matrix from the information given and write down each firm's strategies. (6 marks) b. Determine whether or not a dominant strategy equilibrium exists in this duopoly game. In your analysis, clearly show how each player chooses their strategy. (12 marks) c. What is the Nash equilibrium of this game? Explain in detail how you arrived at your answer. (12 marks) d. One policy analyst said Pfizer and AstraZeneca are engaged in a Prisoner's dilemma game. Do you agree or disagree with this analyst? Critically discuss. (10 marks)