Answer:
The two main characteristics of the market structure where Telkom operates before the emergence of the big three are:
1. Profit-maximization as the single seller and price-fixer
2. High barriers to entry of all entities backed by government regulations
Step-by-step explanation:
Telkom was the only fixed-line and state-owned monopolist in South Africa until the mid-1990s when the big three telecom competitors emerged following deregulation. During the era when it was a monopolist, Telkom was the only provider of fixed-line telephone services. At that time, mobile networks had not been introduced. As a single seller of its services, Telkom practiced price discrimination and maximized profits, ensuring that the barriers to entry of other companies were strongly protected by law.