What is a sightholder, and how did De Beers' sight system influence diamond pricing and market control?

What is a sightholder, and how did De Beers' sight system influence diamond pricing and market control?

• A. A sightholder is a buyer granted regular access to rough diamonds at set prices; De Beers used sights to coordinate supply, stabilize prices, and manage demand.
• B. A sightholder is a diamond miner; De Beers used sights to test for quality.
• C. A sightholder is a retailer who sells only polished stones; De Beers used sights to advertise.
• D. A sightholder is a government regulator; De Beers used sights to set taxation.

Answer: (D)