A monopoly, unlike a perfectly competitive firm, has some market power. Thus, it can raise its price, within limits, without quantity demanded falling to zero. The main way monopolies retain their market power is through barriers to entry, which prevent other companies from entering monopolized markets and competing for customers. Consider the market for tanzanite. The mines for this blue-purple gemstone, found only in Tanzania, are owned by the local government. Given that no one is allowed into the mines without government permission, the market structure for tanzanite highly resembles that of a monopoly. Which of the following best explains the barriers to entry that exist in this scenario?
A. Exclusive ownership of a necessary resource
B. Legal barriers
C. Increasing returns to scale

No other nation can get into the market of this business as the resource is found only in Tanzania. This depicts that Tanzanian government have the ultimate power in this market as they are the sole owners of the resource, thus its has exclusive rights barriers externally.

However, internally Tanzania has legal barriers as no private firm or oterh such entity can get into the extraction of the gems without the permission from the government.