Which of the following are assumptions made in the model of pure monopoly?
A. The firm is a single-price monopolist; it charges the same price for all units of output.
B. No unit of government regulates the firm.
C. The government regulates the firm.
D. The firm is a multi-price monopolist; it charges different prices for all units of output.
E. Patents, economies of scale, and resource ownership secure the firm's monopoly.