The firm described in​ Natural Monopolies in Economics is a natural monopoly. The firm described in​ Monopoly and Antitrust Policy is a monopoly and it may be a legal monopoly. The firm described in​ Market Structure and Pricing Strategy can price discriminate because​ it has market power.

a. it faces downward-sloping demand curve
b. there are no close substitutes for its product
c. it has different price elasticity of demand in different market segments
d. it has control over the entire supply chain
e. it has significant barriers to entry.