Which of the Following Statements Is NOT True Regarding DeBeers

Which of the following statements is NOT true regarding DeBeers' rise to monopoly power in the diamond market?

A) DeBeers produces about 40 percent of the world's raw diamonds and controls another 30 percent.
B) DeBeers achieved dominance in this market by gaining control of South Africa's Kimberley "pipe," the world's largest source in the late nineteenth century.
C) DeBeers carefully limited the amount of diamonds it released into the market.
D) DeBeers did not worry about diamonds being discovered elsewhere because it already had full control of the industry in South Africa.