Which of the Following Statements Is True

Which of the following statements is true?

A) Regulations on cigarette marketing and advertising are decided and enforced by state governments.
B) Cigarette manufacturers have voluntarily limited their marketing efforts in the United States as the health dangers of tobacco became apparent.
C) In the developing world, where tobacco regulation is often lacking, cigarette manufacturers give away cigarettes or offer them at a steep discount to encourage smoking.
D) All of these are correct.