In 1973, why did the Arab oil-producing countries stop selling oil to the United States? A. They were angered that the U.S. had assisted Israel during the Yom Kippur War. B. They had exhausted their oil reserves and had no oil to sell. C. The price of oil had fallen significantly, and it was no longer profitable for them to sell it. D. The United States increased its domestic production of oil and no longer needed to import it.